An electric compressor includes a motor, a scroll compression mechanism, a housing, a circuit unit, a circuit housing housing the circuit unit and integrated with the housing. The electric compressor includes a heat sink provided on a circuit unit side of a partition wall so as to project to be brought into contact with a semiconductor element of a power substrate, facing the partition wall that erects along a vertical direction to separate the inside of the housing from the circuit housing. The heat sink has a lower surface and an upper surface formed into a cylindrical shape so that width of an upper end portion and a lower end portion of the heat sink gradually decreases to reach a tip portion.