To provide a motor-driven pump in which a drive circuit part is cooled while suppressing increases of parts in number and the assembling man-hours.

This motor-driven pump 1 comprises: a stator 14 forming a rotating magnetic field; a rotor 30 having a motor shaft 31 and arranged in the stator 14; a wiring board 17 having the drive circuit part for supplying power to the stator 14 and hall ICs 21, 22 detecting a sensor magnet 23, a first bearing housing 53 and a second bearing housing 58 supporting the motor shaft 31; a cylindrical can 57 having both ends fitted to both bearing housings 53, 58 and partitioning a stator atmosphere from a rotor atmosphere; a casing 51 connected to the stator 14 and forming a pump chamber 74; and an impeller 77 secured to the motor shaft 31 in the pump chamber 74. Vane parts 24, 25 are formed on the sensor magnet 23 secured to the wiring board side ends of the motor shaft 31, and the sensor magnet 23 is sealed airtight by a cover 66 fitted to the second bearing housing 58.