To improve the efficiency of working when mounting an electronic control device on a transaxle including two rotary electric machines.

An upper surface 62 of a transaxle case 40 is sloped in nearly parallel to a common contact plane of two rotary electric machines. The electronic control device 42 is arranged on an upper surface 62 of the case so that pins 58 disposed at a lower surface of the electronic control device are inserted in a guide groove arranged at the upper surface of the case. The electronic control device is moved along with the slope of the upper surface of the case. By the movement thereof, a bus bar 56 of the electronic control device side approaches from a transverse direction to a bus bar 64 of the rotary electric machine side and contacts each other.