The disk-chucking device includes a chuck base having a plurality of arranging parts recessed along an outer periphery of the chuck base and formed at the center of the chuck base with a central boss connected to the motor, a plurality of chuck pins respectively assembled to the arranging parts, a plurality of spring members elastically supporting a rear end of the chuck pins forwardly such that a leading end of the chuck pins can be exposed to an outer surface of the chuck base, and a rigid frame contacting the spring members and formed with a central hole such that the central hole has an inner diameter larger than an outer diameter of the central boss, thereby providing a degree of freedom, which allows the rigid frame to be moved in a horizontal direction within an allowable range.