According to an embodiment of the present disclosure, an apparatus is configured to perform a solution process by supplying a processing solution from a processing solution supply source to the substrate held on a substrate holder via a flow path member and a nozzle at a flow rate equal to or less than 1 mL/sec. The apparatus includes a solution transfer unit configured to transfer the processing solution to the nozzle, and mounted to the flow path member, and an ultrasonic flowmeter mounted to the flow path member at a downstream side from the solution transfer unit. In this embodiment, a lower limit of a flow rate range which is measured by the ultrasonic flowmeter is equal to or less than 1 mL/sec.