An electrostatic chuck for attracting an insulative substrate to be processed, the electrostatic chuck comprising a dielectric layer having a first surface which attracts an insulative substrate, and a second surface on which are provided a plurality of electrodes, and an insulative support base plate fixing said dielectric layer. A distance between adjacent ones of the electrodes and the thickness of the dielectric layer are adjusted such that when a potential difference is established between the electrodes, a non-uniform electric field is formed in which the insulative substrate is partially polarized and attracted to the first surface by gradient force.