To provide a power supply relay controller and an electric power steering apparatus capable of appropriately preventing contact failure of relays. When abnormal conduction between relay contacts occurs, a power supply relay circuit is opened and closed while a predetermined potential difference is applied between the relay contacts. At this time, an operation for turning on the relay contacts is performed while the charge of an electrolytic capacitor by a precharge circuit is limited. In this way, an ice layer between the relay contacts is removed by thermal energy of an arc that is generated between the contacts by a potential difference between the relay contacts.