To prevent a disk from breaking owing to a d disk setting failure when the opening/closing lid of a disk player is closed, as to the chucking device of the disk player.

This device is equipped with a chuck holder 12 which is fitted to the opening/closing lid 1, a yoke plate 14 which moves up and down while engaging the chuck holder 12 and can come into contact with the opening/ closing lid 1, a chuck disk 13 which is fitted detachably to the yoke plate 14 containing a magnet 15 at an upper position, and a sensing means 29 which generates a warning sound or makes a warning display when sensing the contacting of the yoke plate 14 fitted to the opening/closing lid 1.