To provide an electrostatic chuck, including: a ceramic dielectric substrate having a first major surface on which an object to be processed is mounted, and a second major surface on a side opposite the first major surface, the ceramic dielectric substrate being a polycrystalline ceramic sintered body; and an electrode layer interposed between the first major surface and the second major surface of the ceramic dielectric substrate, the electrode layer being integrally sintered with the ceramic dielectric substrate, and the electrode layer includes a first portion having conductivity, and a second portion that bonds the first dielectric layer and the second dielectric layer, and the mean grain size of crystals included in the second portion is smaller than the mean grain size of crystals included in the ceramic dielectric substrate.