A method of processing a substrate, includes: mounting at least one substrate on at least one substrate holder configured to rotate about an axis of the at least one substrate holder, the at least one substrate holder being provided along a circumferential direction of a rotary table installed inside a processing chamber; holding the at least one substrate by the at least one substrate holder in a contact manner by bringing a substrate contact portion into contact with at least three points on a lateral surface of the at least one substrate mounted on the at least one substrate holder; and performing a substrate process while rotating the rotary table and rotating the at least one substrate holder about the axis of the at least one substrate holder in a state where the at least one substrate is held by the at least one substrate holder in the contact manner.