First, you will have to check if bank will lend you a housing loan. Because you can not buy a house without money and housing loan is very difficult. especially for foreigners.
It is completely different from other loans<car or cash and credit card>. It must apply to all of the following contents.
Basic bank requirement
1. Japanese or Permanent residence
2. Employment form is only Seishain <not Keiyku or hakenshain and jiei>
3. Yearly income is more than 400man.<total with partner is OK>
4. Length of service is more than 3 year<current company>
5. Age is under 40.
6. Japanese ability is more than 70% ※<Kanji, Katakana, Hiragana> also writing
7. Saving money is more than 100 man
8. Borrowing amount 20 million or less
9. You do not have a loan <car,credit card ribo,etc…all loans>
10. You do not have experienced a delay in loan payment. last 7 years <mobile phone, credit card, etc…>
I am afriad that there are few people who apply to all. If you apply to all the above contents, there are no problems. However, I am afraid that there are few people applicable.
So,If you really will want to your own house, you will have to find the applicable bank that fits you. And you will have to negotiate that bank. It is impossible to do it in reality, so I will do it for you.