[Ichiro614]

As others have mentioned, if your Japanese skills are not at an advanced level, taking classes that are taught in Japanese will be extremely challenging to say the least.

You might want to consider simply studying Japanese at your home country's university along with whatever other major you are interested in pursuing, do a foreign exchange for a year, and then maybe consider doing graduate work in Japan.

If you really do want to pursue a degree in Japan, in addition to the other schools mentioned Tsukuba University, where I spent a year, is another school that accepts many foreign students and also has a Japanese language program for those who first need to get their skills up to speed.

The Stanford Inter-University Center in Yokohama (where I also spent a year) is another great program if your focus is on improving your Japanese, although this program is mainly for grad students.