is freelancing popular in japan?

i am just wondering if there are a lot of freelancers in japan. since japan tends to work and stay in one company during their lifetime, i wonder if there are a lot who also choose to go freelance or build startup instead.

since japan tends to work and stay in one company during their lifetime

Only if the company is comfortable and stable enough. Ever since the so-called "bubble economy" collapsed in the early 90s, economical situations and people's values have changed. Besides, many large enterprises went bankrupt forcing employees to go freelance. Plus, we now have the personal computer and many other digital devices, which makes it easier to go SOHO. Freelancing is also a good way to work and look after your aging parents or young children, which are issues that Japan is facing now.

So although it's not necessarily the best way to work, it's a popular way to work.

if freelancing is popular, why it seems that freelancer.com and elance are not popular in japan?

Sorry, I was talking about Japanese freelancers like me. At least that's the impression I got from your original question. And needless to say, typical Japanese freelancers can't read those two websites. As for myself, I'd never heard of them. A lot of people seem to "stumble into" freelancing, which was also the case for me. I don't know if freelancing is popular among expats, but I do know several of them.

I know several people doing freelance web design, translation, and other services, and of course there are Japanese people building apps, launching start-ups, etc. English-language freelancing sites wouldn't be of any use to Japanese freelancers, just as Japanese sites like lancers.jp wouldn't be of much use to English speakers. I wouldn't say it's a popular way to work (though the lifetime employment you seem to be thinking is common is actually becoming a thing of the past), but it's becoming more well known.

thanks for your input. i guess i need to make my question more general instead of specifying english sites.
do japanese freelancers use or rely heavily on freelancing websites?
how does freelancing works here in japan?
which is the most common way of getting a clients for japanese freelancers? do they apply in job fairs? apply to companies directly? or freelancing sites?

The answers to your questions differ greatly depending on the field and indivisual.

For example, like I said, a lot of freelancers seem to stumble into freelancing. What I mean is that a person may be working as an employee or taking a long vacation for one reason or another (such as childcare), and a friend offers the person a job. One thing leads to another, and the person becomes a freelancer and quits the company (s)he belonged to. In cases like these, the person doesn't really have to rely on websites or fairs.

Or some people get registered to websites and agents that specify on one field. For example, I know translators who are registered to groups that specify on translating alone.

I do know a freelancer that organizes fairs. She's like a freelance organizer of fairs. I've been invited by her to a fair and it was big and fun, although I'm not sure how many name cards led to success on that fair alone.

Meanwhile, there are a lot of fields where clients tend to avoid adventures. Or in other words, in those fields adventures don't really work. What I mean is that, a client might randomly hire a person who is registered somewhere, but ends up stuck with a job poorly done. So, in those fields, clients seek for recommendations. In other words, freelancers in those fields can hardly get new jobs without recommendations from their colleagues or mentors.

So it works in every way. I think that that is the reason they call it freelancing. One of the best ways to start is to seek advise from successful freelancers of the field you want to work for. You need friends anyway when you're working alone.

I have worked in crowdsourcing.
Lancers
Crowdworks
Shufti
While working mainly in the three, two of the above is a big site in Japan of crowdsourcing.
Japanese, including me, there are many people English is not good.
It is also because many of the English sentence has been translated into Japanese.
Because there is quite a large market in Japan of crowdsourcing, there are many people who do not work in English of the site.
Even if the work in the United States and Australia of site, not very high unit price when from Japan of price.
In addition, people who have the professional skills (for example, programs and design), but earn enough to live, do not earn until there is a lot of people.
If more unit price goes up, crowdsourcing might be a little more crowded.