Device for correcting reference position for transfer mechanism, and correction method

A conveying mechanism ( 22 ) is disposed in a conveying vessel ( 10 ). The conveying mechanism includes: a moving member ( 38 ) which can move in a horizontal moving direction; a rotary table ( 48 ) attached to the moving member such that the rotary table can turn in a horizontal turning direction and move in the vertical direction; and two arm mechanisms which can bend and stretch in a horizontal operating direction relative to the rotary table. A reference position correcting device for the conveying mechanism includes: a light emitter ( 66 ) for emitting a sensing light beam (L); a light detector ( 68 ) for receiving the sensing light beam; and correcting means ( 62 ). The light emitter and the light detector are fixedly positioned on the conveying vessel. The correcting means corrects reference positions of the rotary table in the moving, vertical, and turning directions, and corrects a reference position of each of the arm mechanisms in the operating direction, based on a detection by the light detector about a light-transmitting state and a light-shielding state of the sensing light beam switched in compliance with the movement and the turn of the rotary table. A light-shielding member is attached on the rotary table, for switching the sensing light beam between the light-transmitting state and the light-shielding state, in compliance with the movement and the turn of the rotary table.