A brake cylinder device (2, 3) comprising: a cylinder body having a hollow interior; a piston (22, 50) that defines a pressure chamber inside the cylinder body and to which a biasing force generated by a piston spring is transmitted, the piston (22, 50) moving relative to the cylinder body against the biasing force of the piston spring by supply of pressure fluid to the pressure chamber; a brake output portion that is provided so as to be movable together with the piston or provided so as to be movable via a force amplifying mechanism for amplifying a force generated in the piston as a result of movement of the piston, the brake output portion being movable in a braking direction in which it projects from the cylinder body and an anti-braking direction in which it approaches the cylinder body; a threaded shaft that is connected to the brake output portion and has a thread formed on an outer circumference thereof; characterized in that it comprises a guide tube that is attached to the piston or the force amplifying mechanism and accommodates the threaded shaft thereinside; a pusher spring disposed so as to be capable of biasing the threaded shaft toward the braking direction to the guide tube or the piston; a clutch nut for threadably engaging with a tip of the threaded shaft disposed on the brake output portion side with respect to the cylinder body; a front stopper disposed so as to be capable of coming into contact with the clutch nut on a front side, which is the brake output portion side with respect to the clutch nut such that a movement of the clutch nut with respect to the guide tube is restricted, and biasing the clutch nut and the threaded shaft in the anti-braking direction together with a movement of the guide tube in the anti-braking direction; a first clutch disposed so as to be capable of coming into contact with the clutch nut via a predetermined interval from the front stopper on a rear side, which is a side opposite to the brake output portion side with respect to the clutch nut; an adjustment stopper that is disposed so as to be movable relative to the clutch nut and the guide tube along the axial direction of the threaded shaft and whose movable range is restricted with respect to the cylinder body; a second clutch to which the adjustment stopper is fixed, and that is disposed so as to be capable of coming into contact with the clutch nut on the rear side; and an adjustment spring that is in contact with or connected to the adjustment stopper or the second clutch at a first end thereof and is capable of biasing the clutch nut toward the anti-braking direction. a cylinder body having a hollow interior; a piston (22, 50) that defines a pressure chamber inside the cylinder body and to which a biasing force generated by a piston spring is transmitted, the piston (22, 50) moving relative to the cylinder body against the biasing force of the piston spring by supply of pressure fluid to the pressure chamber; a brake output portion that is provided so as to be movable together with the piston or provided so as to be movable via a force amplifying mechanism for amplifying a force generated in the piston as a result of movement of the piston, the brake output portion being movable in a braking direction in which it projects from the cylinder body and an anti-braking direction in which it approaches the cylinder body; a threaded shaft that is connected to the brake output portion and has a thread formed on an outer circumference thereof; characterized in that it comprises a guide tube that is attached to the piston or the force amplifying mechanism and accommodates the threaded shaft thereinside; a pusher spring disposed so as to be capable of biasing the threaded shaft toward the braking direction to the guide tube or the piston; a clutch nut for threadably engaging with a tip of the threaded shaft disposed on the brake output portion side with respect to the cylinder body; a front stopper disposed so as to be capable of coming into contact with the clutch nut on a front side, which is the brake output portion side with respect to the clutch nut such that a movement of the clutch nut with respect to the guide tube is restricted, and biasing the clutch nut and the threaded shaft in the anti-braking direction together with a movement of the guide tube in the anti-braking direction; a first clutch disposed so as to be capable of coming into contact with the clutch nut via a predetermined interval from the front stopper on a rear side, which is a side opposite to the brake output portion side with respect to the clutch nut; an adjustment stopper that is disposed so as to be movable relative to the clutch nut and the guide tube along the axial direction of the threaded shaft and whose movable range is restricted with respect to the cylinder body; a second clutch to which the adjustment stopper is fixed, and that is disposed so as to be capable of coming into contact with the clutch nut on the rear side; and an adjustment spring that is in contact with or connected to the adjustment stopper or the second clutch at a first end thereof and is capable of biasing the clutch nut toward the anti-braking direction.