A flow rate control device (100) comprises: a pressure control valve (6) provided in a flow path; a flow rate control valve (8) provided downstream side of the pressure control valve; and a first pressure sensor (3) for measuring pressure on the downstream side of the pressure control valve and on the upstream side of the flow rate control valve. The flow rate control valve has a valve element (13) seated on/separated from a valve seat (12); a piezoelectric element (10b) for moving the valve element so as be seated on/separated from the valve seat; and a strain sensor (20) provided on a side surface of the piezoelectric element. The pressure control valve (6) is configured to control the pressure control valve (6) on the basis of a signal output from the first pressure sensor (3), and to control the driving of the piezoelectric element of the flow rate control valve (8) based on a signal output from the strain sensor (20).