A magnetic chuck includes a first cylinder (12) and a second cylinder (64) that are arranged in series with each other. A first piston (28) of the first cylinder includes a permanent magnet (36), and a piston rod (44) connected to the first piston is inserted into a second piston (76) of the second cylinder. A stopper (90) that can abut against the second piston is fixed to the piston rod. The position of the stopper can be changed relative to the piston rod.