A scroll compressor which can be easily sealed and assembled is presented. Also a scroll compressor which can be sealed easily and at low cost is presented. It includes a cylindrical front casing with a bottom, a rear cover to be fitted to the inner circumference of the front casing, a fixed scroll having an end plate to be fitted to the inner circumference, a fitting portion to be fitted concentrically to the rear cover, and a spiral blade disposed at the opposite side of the fitting portion, a movable scroll engaged with the fixed scroll and swiveling at a specified radius of swivel, and a rotation preventive mechanism for preventing rotation of the movable scroll and permitting swivel motion only. By assembling the fixed scroll and rear cover, a nearly triangular recess is formed in the butt junction of the end plate and rear cover, a seal member is fitted into the recess, and the fixed scroll and rear cover fitting the seal member are assembled into the front casing, thereby sealing both between the suction pressure and discharge pressure, and between the atmospheric pressure and discharge pressure.