Electrostatic chuck

The purpose of the present invention is to provide an electrostatic chuck capable of suppressing the influence of positional deviation of a refrigerant flow path. Provided is an electrostatic chuck provided with: a ceramic dielectric substrate; and a base plate that supports the ceramic dielectric substrate and has an upper surface on the ceramic dielectric substrate side and a lower surface on the opposite side of the upper surface, the base plate including a communication path that is provided between the upper surface and the lower surface and through which a refrigerant can pass, the communication path including a first flow path portion having a pair of side surfaces in a first direction, and a second flow path portion having a pair of side surfaces in a second direction. One of the pair of side surfaces has, when viewed along a lamination direction of the base plate and the ceramic dielectric substrate, a plurality of protrusions that protrude in a second direction that is perpendicular to the first dir