A fuel supply device (1) has a valve (13) in a fuel passage between a fuel pump (3) and an engine (5). In a storage portion of an ECU (18-21) is stored a relationship between a fuel pressure and a flow rate, which are required by the engine, and voltage which is supplied to a motor (7). The ECU senses voltages V26, V27, V28 supplied to the motor from a controller (22) when the valve is opened from change points C1′, C2′, C3′ at which a characteristic between the voltage and the current which are supplied to the motor (7) is changed. Then, the ECU corrects the voltage stored in the storage portion on the basis of differences between voltages V1, V2, V5 stored in the storage portion at the change points C1, C2, C3 and the voltages V26, V27, V28 when the valve is opened. In this way, the fuel supply device can correctly control the motor in correspondence to the fuel pressure and the flow rate which are required by the engine.