The power generation controller, which is for regulating an output voltage of a vehicle generator or a battery voltage of a vehicle battery charged by the vehicle generator by controlling an excitation current flowing into an excitation winding of the vehicle generator, includes a switching element connected in series between an output terminal of the vehicle generator and the excitation winding, a voltage control circuit on/off controlling the switching element such that one of the output voltage of the vehicle generator and the battery voltage is kept at a target voltage, and a contact abnormality detector circuit detecting a voltage of the output terminal as the output voltage of the vehicle generator, and detecting abnormality in a contact state between the power generation controller and the output terminal on the basis of the detected output voltage of the vehicle generator.