An object of the present invention is to provide a refrigerant compressor in which amount of discharge that is removed to a refrigerant circuit of lubricating oil that is supplied to a compressing mechanism is reduced. The refrigerant compressor includes: an electric motor that is constituted by a stator and a rotor that are disposed inside a sealed vessel; a compressing mechanism that is driven by a crank shaft that is fitted into the rotor; a lower portion oil pool that stores in the sealed vessel a lubricating oil that lubricates the compressing mechanism; and an upper counterweight that is disposed on an upper end of the rotor, refrigerant gas that is compressed by the compressing mechanism being discharged inside the sealed vessel, and the discharged refrigerant gas passing through a gas channel that is formed on the electric motor, being moved from a lower space to an upper space with respect to the electric motor, and then being discharged outside the sealed vessel. An oil return flow channel is formed on the upper end of the rotor toward a lower end from a vicinity of a leading end portion of the upper counterweight in a direction of rotation, and oil that is expressed in a vicinity of the rotor is directed to the oil return flow channel.