According to the present invention, there are provided a self-bias measurement method of measuring the self-bias voltage of an object when the object is subjected to a plasma process by using a plasma generated between a pair of electrodes, the object being held, by means of electrostatic chucking means having an electrostatic chucking electrode, on one of the pair of electrodes situated in a processing chamber, the method including the steps of detecting a leak current between the object and the electrostatic chucking electrode while varying the DC voltage applied to the electrostatic chucking electrode, and calculating the self-bias voltage of the object on the basis of the leak current detected, an apparatus for measuring the self-bias, and an electrostatic chucking apparatus having means capable of measuring the self-bias.