There is provided an electric supercharger having a compressor including a compressor impeller, a motor housing, an electric motor rotationally driving the compressor, and a first bearing and a second bearing provided to support a shaft and a rotor in the motor housing. The first bearing is located on the compressor side of the rotor and the second bearing is located on the other side of the rotor. The motor housing includes a thermal conductive passage through which heat generated by a coil wound around a stator is transmitted to the first and second bearings. The thermal conductive passage between the coil and the first bearing is formed with a reduced thickness portion in such a way that thickness of the thermal conductive passage is reduced in a direction that is perpendicular to a direction in which the heat is transmitted through the thermal conductive passage.