PURPOSE: To conform the longitudinal movement of the piston of an air cylinder in a nailing machine and timing when a switch operating the nailing machine is turned ON when nails are driven continuously in an automatic nailing device.

CONSTITUTION: When a second solenoid valve SOL2 is turned ON, a nailing machine A is forward moved by a cylinder device 10, and the movement is detected by a limit switch LS2. A first solenoid valve SOL1 is turned ON by the limit switch LS2, and the nailing machine A is operated while a timer is worked. The solenoid valves SOL1, SOL2 are turned OFF by the timer, and the solenoid valves SOL1, SOL2 are not turned ON until a limit switch LS1 detects the nailing machine A again.