To improve a heat dissipation property of a motor and reduce a cost for manufacturing the motor since the quantity of an injected resin molding material is reduced in the electric motor having a concentrated winding.

A stator 13 of the electric motor 10 has the concentrated winding as coils 18 wound onto a plurality of teeth formed in an iron core 17. A case 11 is provided with a cylinder 11a fitted on an outer circumference of the stator 13, and an end plate 11b integrally formed at one end of the cylinder 11a and facing coil ends 18a. When a resin is injected into the stator 13 in a state that the stator 13 is assembled into the case 11, a mold 20 is formed. A rib 23 is integrally provided in the case 11, protrudes into a gap between the coils, and radially extends between the coil ends 18a.

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