A scroll type refrigerant compressor having a stationary scroll unit, a movable scroll unit including an orbiting spiral member engaged with the stationary scroll unit to define variable-volume compression chambers in which the refrigerant gas is compressed in response to a rotation of a drive shaft having an eccentrically arranged drive key member, and a drive bushing member having an aperture formed therein in which the drive key of the drive shaft is inserted so as to cause an eccentric motion of the drive bushing member operatively engaged with the movable spiral member to thereby drive an orbiting motion of the movable spiral member. The drive key member is formed as an axial columnar mechanical member having a central axis thereof parallel with the axis of rotation of the drive shaft and a diametrical axis thereof intercrossing the central axis at a predetermined point, the diametrical axis of the drive key member being arranged so as to be angularly shifted by a predetermined angle in a direction reverse to the rotating direction of the drive shaft with regard to a predetermined axis passing through the axis of rotation of the drive shaft, the predetermined point of the drive key member being arranged in an area extending in a direction reverse to the rotating direction of the drive shaft with regard to a line connecting the axis of rotation of said drive shaft and the central axis of said drive bushing member, the drive key member further having planar faces disposed on both sides of the diametrical axis thereof, and two spaced ends, each of the two spaced ends being distant from the central axis of the drive shaft.