A substrate treating apparatus, in which a voltage is applied to between a treatment electrode and a target substrate in such a state that the treatment electrode is opposed to the target substrate to thereby perform substrate treatment for removing undesired substances on the target substrate, has a reference electrode, a transfer unit which transfers at least one of the treatment electrode and the reference electrode to thereby provide the treatment electrode so that the treatment electrode is opposed to the reference electrode, and a check unit for applying a voltage to between the treatment electrode and the reference electrode in such a state that the treatment electrode is opposed to the reference electrode and thereby checking an adhesion level of undesired substances onto the treatment electrode surface.