To provide a differential inexpensive and easy to handle, to smoothly turn by using a spur gear inexpensive and mass-producible, in place of a bevel gear.

The differential usually uses the bevel gear. However, the bevel gear is not productive as compared with the spur gear in manufacturing, and twice or three times as expensive as the spur gear. When the spur gear is adopted, material cost is low and machining is easy. As a method for achieving this, two spur gears 3a, 3b coupled with wheel shafts inside two bowl-shaped housings, and two planetary spur gears 4a, 5a of two shafts held by the housings are respectively meshed to drive the housing. Thereby, the differential of which a structure is simple, which is inexpensive and is easy to handle, can be achieved.