A cartridge chucking apparatus capable of stably and correctly restricting the position of a cartridge with an improved reliability and precision. A cartridge (1) is provided with a circle hole (2a) and an elongated hole (2b) as reference holes (2) for restricting an in-plane position of the cartridge (1). The cartridge chucking apparatus has: a loading chassis (10) having projections (12a, 12b and 12c) for holding the cartridge (1) and restricting the position in the height direction and support shafts (14a and 14b) for supporting the loading chassis while it is raised or lowered; a base chassis (20) having reference planes (22a, 22b and 22c) for squeezing the cartridge (1) with the projections (12) at a recording/reproducing position of the loading chassis (10) to restrict the position in the height direction and positioning pins (22b and 22c) formed on the reference planes (22b and 22c) for being inserted into the reference holes (2) to restrict an in-plane position of the cartridge; and elastic members (3a, 3b and 3c) for energizing the loading chassis (10) so that first the positioning pin (28c) is inserted into the circle hole (2a) of the cartridge (1).
