The substrate processing apparatus includes common piping which guides a processing liquid to a branching portion, supply piping which guides the processing liquid from the branching portion to a chemical liquid nozzle, return piping which guides the processing liquid from the branching portion, and a discharge valve which changes a flow rate of the processing liquid supplied from the common piping to the branching portion. The discharge valve makes a valve element stationary at a plurality of positions including a discharge execution position at which the processing liquid is supplied from the common piping to the branching portion at a flow rate larger than a maximum value of a suction flow rate and a discharge stop position at which the processing liquid is supplied from the common piping to the branching portion at a flow rate smaller than the maximum value of the suction flow rate.