A scroll compressor for compressing a gaseous refrigerant including a lubricant in a mist state, having a stationary scroll member and a movable scroll member, which define pump chambers at an outer wall side of the movable scroll member and an inner wall side of the movable scroll member, which chambers are initially opened to an inlet port via a main intake passageway for introducing a gaseous refrigerant into the chambers when they are radially outwardly located. A sub-intake passageway, in which a shaft seal unit is provided, is diverted from the main intake passageway and is opened to the outer wall sided chamber before the chamber is sealingly closed so that a flow of gas, from the inlet port, is introduced into the chamber, the gas is positively fed to the shaft seal unit, and the shaft seal unit is lubricated.