Yokohama city (2nd biggest city in Japan) official runs three zoos. The oldest one is Nogeyama zoo. You can enter Nogeyama zoo without fee (admission fee is 0 yen). Other two are Kanazawa zoo and Zoorasia. Admission fee of Kanazawa zoo is 500 yen ($5.32 €4.10), and admission fee of Zoorasia is 600 yen ($6.38 €4.92).
I have been to Nogeyama zoo today. Unfortunately it was very crowded, and my son and I could not see animals well.
Asiatic black bear