International students get permission to work as a part time work only when it is clear that working is not adversely effecting studies. Students have to enrolled in class.
As a part-time work, students are only allowed to work only 28hrs/week during classes and 40 hrs/week during the holiday. Part-time working permission can be obtained at the airport who are entering to Japan for the first time as a student. I will recommend you to make this in Airport Otherwise you have to go several time to the Immigration Bureau.You may have to wait for a several weeks and sometimes a month.

The company or a job provider asks you for a copy of your residence card for the records. If you are student there must be written about the time you can work in the back of your residence card. If nothing is written in the back of your residence card, you can’t work. The work permit expires on the same date as your residence card stay.

Students must not be engage in any prohibited work.Here are the lists

• night clubs
• adult entertainment industry
• hostess clubs
• pachinko parlour
• escort services
• Doorman,Bouncer
• even dish washing at a bar
• dating sites