A stator of a motor comprises a stator core including a plurality of plate members stacked together; the stator core including: a yoke of a tubular shape; and teeth each of which includes an extending portion extending inward in a radial direction of the yoke from the yoke and an increased-width portion formed at a tip end of the extending portion so as to have a greater width than the extending portion in a circumferential direction of the yoke; wherein the extending portion has a constant-width portion extending radially in a straight-line shape so as to have a constant circumferential width, a narrower portion having a circumferential width smaller than a circumferential width of the constant-width portion, and a clamp portion for securing the plurality of plate members to each other; and wherein at least a portion of the clamp portion is located in the narrower portion.