Insulators are formed of a resin material using injection molding and provided at an end portion in an axial direction of a cylindrical stator included in a motor. Each of the insulators includes a wall portion that is formed in a cylindrical shape; a plurality of winding drum portions that consecutively extend from the wall portion so as to be along one end surface in an axial direction of the wall portion from an inner peripheral surface of the wall portion toward an inner side in a radial direction of the wall portion; and a plurality of opening portions that are formed between the respective winding drum portions, which are adjacent in the circumferential direction of the wall portion. A gate mark, which indicates an injection location of the resin material, is formed on the one end surface in the axial direction of the wall portion.