When you want to obtain a permit to engage in activities not allowed by your present permit
If you wish to engage in activities which are not allowed by your present status permit and from which you will earn an income, you must apply for a permit at the immigration bureau for your district.
Example: An overseas student who wants to work part-time

Required documents:
The documents required will vary depending on ones status of residence and conditions of stay. For details, enquire at the immigration bureau for your district.

Note 1 The information given is that confirmed as of July 2002. Note that a new system or system revisions may have been introduced after this date.

This information is from the CLAIR website. The Council of Local Authorities for International Relations (CLAIR) was established in July 1988 in response to rising concerns about local level internationalization in Japan.