Abstract: A substrate-processing-apparatus includes a processing-vessel to accommodate a substrate and to process the substrate; a substrate-support that is provided inside the processing-vessel and has a mounting-surface on which the substrate is mounted; and a lift-pin-mechanism that includes a lift-pin that is movable relative to the substrate-support and a pin-housing-chamber in which the lift-pin is housed, the lift-pin-mechanism being to lift the substrate by raising the lift-pin, wherein the substrate-support has a hole through which the lift-pin is passable, the lift-pin mechanism includes a pressure-regulator that regulates the pressure in the hole by passing inert-gas through the pin-housing-chamber, and at a timing when the substrate is to be lifted, the pressure-regulator adjusts the pressure in the hole to a lifting pressure that is greater than or equal to the pressure in a processing space that is above the mounting-surface and at which the substrate remains continuously mounted on the mounting-surface.