A stator includes a first stator part, a second stator part, and an annular seal member. The annular seal member is provided with a plurality of protrusions extending radially outward. A groove part corresponding to the annular seal member, and a plurality of recessed parts, which correspond to the plurality of protrusions of the annular seal member and which are to be connected to the groove part, are formed in at least one of the first stator part and the second stator part.