Electronic Control Device

Provided is a highly versatile and reliable power supply device (power supply ASIC) that can support electronic devices with a wide range of drive currents while suppressing a cost increase, and an electronic control device using the same. An electronic control device includes: a first power supply circuit that outputs a first voltage; a second power supply circuit that generates a second voltage from the first voltage; and a first MOSFET arranged independently of the first power supply circuit and the second power supply circuit. The second power supply circuit includes: a reference power supply that outputs a reference voltage; an amplifier that amplifies the reference voltage; a second MOSFET connected in parallel with the first MOSFET; a voltage detection unit that detects a voltage value of a gate terminal of the first MOSFET; and a switching unit that connects an output from the amplifier to either the gate terminal of the first MOSFET or a gate terminal of the second MOSFET. The switching unit is controlled based on a voltage value at a start detected by the voltage detection unit.