Core material, stator core, and motor provided with stator core

In a core material according to the present invention, a predetermined number of core pieces, each having a tooth portion and a yoke portion, are connected to each other via connecting portions. Each of the connecting portions includes: a V-shaped notch portion; a through hole that is formed at a tapered portion of the notch portion with a diameter elongated in a connection direction; and a thin portion that is formed outside of the through hole and connects the core pieces to each other. The width of the thin portion is more increased apart from the axis of symmetry of two sides constituting the V shape of the notch portion, and further, an intersection between extension lines of the two sides constituting the V shape lies within 0.3 W from the inner side of the thin portion in a notch direction and within the thin portion when W designates the width of the thin portion along the axis of symmetry.