A room pressure control system includes an air supply valve, an exhaust valve, and controller circuits. One of the controller circuits includes a room pressure correction control circuit that controls the valve operating as a room pressure control valve, between the air supply valve and the exhaust valve, so that the room pressure coincides with a set room pressure value; and processing circuitry that determines whether the room pressure easily fluctuates, determines whether the room pressure is stable, and sets parameters. In particular, the processing circuitry sets a dead zone parameter with which responsiveness of room pressure control is valued when it is determined that the room pressure easily fluctuates and otherwise sets a dead zone parameter with which reduction in the number of operations of the room pressure control valve is valued above the responsiveness of the room pressure control.