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; 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 clutch 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; a rear clutch disposed so as to be capable of coming into contact with the clutch nut via a predetermined interval from the front clutch on a rear side, which is a side opposite to the brake output portion side with respect to the clutch nut; a 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; and an adjustment spring that is in contact with or connected to the stopper 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; 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 clutch 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; a rear clutch disposed so as to be capable of coming into contact with the clutch nut via a predetermined interval from the front clutch on a rear side, which is a side opposite to the brake output portion side with respect to the clutch nut; a 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; and an adjustment spring that is in contact with or connected to the stopper at a first end thereof and is capable of biasing the clutch nut toward the anti-braking direction.