Start personal business with Engineer visa?

Hi, I'm currently employed in Japan with an engineer visa.

I'm considering to resign from my current company to start my own freelancing business, but I wonder if that would have any impact on my visa status?

You would almost certainly need to change visa. Business investor would probably be the right one. You'll need a lot of money to do it though - you need to prove you can capitalize your business.

Google is your friend, there are plenty of resources about this...

"Enginner" resident status doesn't cover freelance work without a regular employer acting as the sponsor.

You can do it. Now problem. You need to change the visa status to busineess. How long you have been in japan. I was also on engineer visa and wanted to do same. Now Japan will offer visa to business category very easily . If you start a corporation company, you can get visa easily

Yes, it takes money and a change in status. For freelance you need to prove you have sufficient contracts/income. Google turns up some good results.