The power generation controller includes a control command receiving section receiving a control command transmitted from an external control unit for controlling an internal combustion engine, a control command holding section holding the control command received by the control command receiving section, and an excitation current control section controlling an excitation current of a generator driven by the internal combustion engine on the basis of the control command held by the control command holding section. The excitation current control section is configured to control the excitation current on the basis of a control command transmitted from the external control unit when the internal combustion engine is in a stopped sate.