According to the embodiment, an electrostatic chuck includes a ceramic dielectric substrate, a base plate, and a porous part. The ceramic dielectric substrate has a first major surface placing a suction object, a second major surface on an opposite side to the first major surface, and a through hole provided from the second to first major surface. The base plate supports the ceramic dielectric substrate and includes a gas introduction path communicating with the through hole. The porous part is provided in the gas introduction path. The porous part includes sparse portions including pores and a dense portion having a higher density than the sparse portions. Each of the sparse portions extends in a first direction from the base plate toward the ceramic dielectric substrate. The dense portion is positioned between the sparse portions. The sparse portions include the pores and a wall portion provided between the pores.