A stator includes a core holder and a stator core configured by split cores arranged so as to form the annular shape, and press-fitted into the core holder. Each of the split cores is configured so that a plurality of metal plates is layered and fixed to each other by dowel-fastening. Each of the split cores includes an outer circumference groove portion and a dowel-fastening portion, the outer circumference groove portion being formed at a portion of an outer circumferential surface of the split core radially outer than the dowel-fastening portion so as to be recessed in a radially inward direction of the stator core to include a predetermined depth.