A pressure control device controls a flow rate of gas supplied to a pressure control target to maintain an inside of the pressure control target at set pressure. The pressure control device includes a controller that is configured to: subtract, at a predetermined ratio, a signal related to the supply of gas from a set pressure signal indicating the set pressure, when gas is being supplied into the pressure control target in order to bring the inside of the pressure control target to the set pressure; compare a detected pressure signal indicating pressure within the pressure control target with the set pressure signal subjected to the subtraction; and control, on the basis of a comparison result obtained by the controller, a flow rate control valve which controls a flow rate of gas supplied to the pressure control target.