A core for use in an axial-gap rotary electric machine is annular and includes a plurality of core pieces into which the core is divided in a circumferential direction. Each core piece includes a yoke portion and a tooth portion that is formed integrally with the yoke portion and that projects from the yoke portion in an axial direction. Each yoke portion includes a plurality of protrusions provided on one side surface connected to the yoke portion of an adjacent one of the core pieces, and a plurality of recesses provided on other side surface connected to the yoke portion of another adjacent one of the core pieces, the recesses corresponding to the protrusions. An interval between the protrusions is 80% or less of a length of the one side surface of the yoke portion, the length being a direct distance between inner and outer peripheries of the yoke portion.