A tray locking apparatus of an optical disk drive including a fixed frame and a tray that moves in and out of the fixed frame to load and unload a disk. The tray locking apparatus includes a first locking portion provided on the fixed frame, and a first lever, that has a second locking portion selectively coupled to the first locking portion, and moves between a coupling position and a releasing position. A first elastic member biases the first lever in a direction toward the coupling position. A switching unit installed at the tray locks the first lever at the coupling position by a magnetic force, and unlocks and moves the first lever to the releasing position by temporarily offsetting the magnetic force. A returning unit makes the first lever return to the coupling position from the releasing position when the tray moves out of the fixed frame.