Tourist to dependent

I am a student in Japan.Im curently studying, i came in japan before 6 month ago.and i have a question.My fiancée is coming to japan under tourist visa for 3 month. If we marrige in japan, and get a marriage certificate, is it gonna be possible to change him status at the immigration office in Tokyo. It is possible change tourist visa to dependent visa within 3 month I would be more than happy if someone could post a detailed answer. It is possible marrige in japan??can we get visa within 3 month??

It is depends on how long does it take to obtain marriage certificate from fiance's (applicant's) country's embassy in Japan.

Offical website of the ministry of justice say that those whose visa expires within 3 month can apply when a half period passed.
http://www.moj.go.jp/ONLINE/IMMIGRATION/ZAIRYU_KOSHIN/zairyu_koshin10_...
It means your fiance has only 1.5 month to apply, even if application is accpected, he will have to leave Japan before his Tourist Visa expire.

As well as the other documents to proof that his spouce (you) are the one who maintain applicant financially with enough income for two or a job in Japan, marriage certificate must be translated into Japanese.
This takes also some time unless you spend huge extra maney for express service.

Anyway, I wish you everhthing go well.
Please be careful with lowyers who offer you assistance for any visa application, I know some who lost money and time.

from my understanding you'll need a lot of funds to support a dependant application - you both can only work limited hours....Given you have no right to stay after your studies i would have thought waiting till you return home would be a better situation

you both can only work limited hours....
Basically working with students visa / dependent visa are ILLEGAL, you NEED to get a WORK PERMISSION in addition to a visa.

In general, it is almost impossible to get a work permission for dependent visa holders (except for those do somehting "behind the door" for the lowyer), especially if their spouce is living in Japan with a student visa, though people think that it is easier to get if spouse is a student because students don't have enough money in general.
The reason is because there are many people who come to Japan to work, taking advantage of student/dependent visa.