To provide a hybrid driving device for setting an over-drive mode, and for preventing shock due to the switching of an operation mode.

The hybrid driving device is provided with: a plurality of locking devices CL and BH for changing the connection relation between rotary elements in any differential gear mechanism 4 and rotary elements in another differential gear mechanism 5 and the fixed status of any rotary element; and a mode switching means 22 for selecting at least two operation modes of an operation mode for accelerating and outputting a power output by an internal-combustion engine 1 and another operation mode in which the relation of the operating status between the internal-combustion engine 1 and an output member is different from that of the operation mode, by switching locking/unlocking state of the locking devices CL and BH, and for switching locking/unlocking state of the locking devices CL and BH in a synchronizing status that the number of rotation of rotary elements whose connection relation with the other rotary elements changes due to the switching is prevented from being changed due to the switching.