Provided is a stator that can easily attach a coil to a tooth and that can reduce concentration of stress generated in the core during the operation. The stator includes a core with an annular back yoke, and a plurality of teeth; and a coil wound around each of the plurality of teeth. The core includes a plurality of divided cores each of which having a divided back yoke. A connecting surface is arranged at an end on a second circumferential side of the divided yoke, the connecting surface being a plane or a convex surface extending from a side surface on the second circumferential side of the tooth to an outer circumferential surface of the divided back yoke.