A controller of a hybrid vehicle includes: a control unit configured to activate a starter device for starting any one of a drive motor and an engine by stepping up electric power from a battery by a voltage transformer. The control unit includes a limitation part that limits passing power of the voltage transformer when the temperature of the voltage transformer rises, and a calculation part that obtains a maximum electric power that can be supplied to the drive motor when the starter device is activated, by subtracting a consumed power of the starter device from limited power during limitation of passing power by the limitation part. The control unit activates the starter device and starts the engine, when required power of the drive motor reaches the maximum electric power calculated by the calculation part during limitation of passing power by the limitation part.