It is an object of the present invention to provide an electrostatic chuck which has a good separation response and scarcely causes gas leakage while keeping the uniformly heating property and high attracting capability for a substrate and a treatment apparatus using the chuck.To solve the above object, an electrostatic chuck according to the present invention comprises a plate-shaped ceramic body in which one main face is a setting face to put an object to be held, the plate-shaped ceramic body having; an electrode on the other main face or inside for electrostatic attraction: a circular projected part formed in the outer circumferential rim part of the setting face, the circular projected part being brought into contact with the object: and through holes formed in the inside of the circular projected part and in the electrostatic, wherein Ra(max) and Ra(min) which denote a maximum value and a minimum value of the arithmetic mean deviation Ra of the face to be brought into contact with the object respectively satisfy {Ra(max)Ra(min)}/Ra(max).ltoreq.0.2.