Substrate processing device and substrate processing method

An object of the invention is to provide technology that can precisely perform desired liquid processing across the entire upper surface of a substrate. A substrate processing device according to one aspect of the invention comprises a holding section, a liquid supply section, a film thickness measurement section, and a control section. The holding section holds and rotates the substrate. The liquid supply section supplies a process liquid to the substrate held by the holding section. The film thickness measurement section measures the film thickness of the process liquid across the entire upper surface of the substrate. The control section controls each section. Further, the control section controls at least one of the rotational speed of the substrate and the supply rate of the process liquid such that the film thickness of the process liquid at all measurement points on the substrate is no greater than a predetermined value.