Paying with card (credit /debit)

I have read that the use of credit/debit cards isn't so spread as in Europe. ¿Can I get difficulties to pay with card in shops o restaurants?

Thank you.

Depends on the city you're visiting.
In Tokyo, credit cards are everywhere now but even still some smaller stores, cafes, and restaurants might not accept CC.

You might do better purchasing an e-money card like Suica or Pasmo or Edy. E-money is more diverse and more shops (even kiosks) accept e-money.

Japan definitely is not like the US where people will pay for a $2 bill with a credit card.

Nothing worse than having the best meal of your life and being told you can't use your credit card, simply because the restaurant doesn't have the hardware for it.
Most places have a few stickers or signs near their cashiers with acceptable payment methods or credit card types written for you, but when in doubt, just whip out your credit card, show it to the shop staff, and ask, "OK?" with a thumbs up or something.
The E-money card is a good idea, but it's the same thing with credit cards: some places accept one or the other e-money card you don't have, or don't have the e-money card equipment. What's wrong with cash?

In Tokyo, credit cards are everywhere now but even still some smaller stores, cafes, and restaurants might not accept CC.

I wouln't say they are "everywhere" the numbers however have increased over the years.

You still cannot buy a regular train ticket with a credit card at most of the regular ticket vending machines.

Most convenience stores don't take credit either, big name fast food places like McDonalds won't take cards either.

Hotels, department stores, and major places like that do accept cards (as in credit/debit cards). Restaurants on the other hand are a hit or miss (look for signs).

Anycase it is good to have cash in hand when traveling around. 85% of transactions done in Japan last year were cash transactions. (Cash to include actual paper money, electronic money, bank transfers etc) rather then credit.

I'm assuming you are from Spain since you have the upside down question mark in your post..!

Your Spanish bank card will not work here - there are a few exceptions however.

If your card has a Visa or Mastercard logo on it (but is a debit, not a credit card) it may work at most large stores and will be useable as a credit card most of the time.

If not though, you can't use it here.

A surprisingly large number of stores in major cities in Japan accept debit as a form of payment now, however, they only work with the large banks like MUFJ, Mizuho, etc.. Shinsei bank does not work at Tokyu hands, I have discovered! But it worked at Yodobashi, Fujiya camera, etc.. Hit and miss. Always be ready to go get cash if it doesn't work.