A hybrid drive device (2) includes a body case (60) having a connection section (61) connected to an engine and receiving a dynamo-electric machine, and also includes an inverter case (10) provided integrally with the body case (60) and receiving an inverter for controlling the dynamo-electric machine. A breather (80) for the inverter is provided to the inverter case (10) on a side wall (12) thereof located on the connection section (61) side, and the breather (80) interconnects the inside of the inverter case (10) and the outside thereof.