Part time work can be a great way to gain a little extra money during your studies, as well as allowing you to develop experience and life skills.
As an International student, your visa will allow part time employment up to 28 hours a week. This work can range from a part time job in the local convenience store to tutoring Junior or High Schools students. Native speakers of European languages such as English, French or Spanish are often in demand in Japan, and can earn significantly higher hourly rates. Of course, nowadays it is not uncommon for students to have a part time job in most countries; however, students working as a language teacher in Japan can earn several times what their hourly rate would be working in a bar or restaurant in their own country. For example, a language teacher earning ¥3,000 per hour working 10 hours a week should be comfortably able to pay their rent and living expenses.
If an international student is to obtain a part-time job (except TA, RA, and tutor), you will have to obtain a work permit from the Regional Immigration Bureau. For details, please refer to the Ministry of Justice's website.