To improve the efficiency of seal member mounting work by easily mounting the seal member into a recessed groove of a lap part.

A large number of slits 32 are formed in a length direction in the inner peripheral surface 31B of the seal member 31 mounted into the recessed groove formed in the lap part of a scroll. The spacing of the respective slits 32 is formed to be small on the inner diameter side located on the radially inside of the seal member 31 and to be large on the outer diameter side located on the radially outside. As a result, the inner diameter side of the seal member 31 is easily bent. The seal member 31 can thereby be easily curved in conformity to the scroll shape of the lap part with a large curvature and easily mounted into the recessed groove of the lap part.