To provide a reference position correction device for a conveying mechanism for correcting the reference positions in all of X-axis direction, Z-axis direction, θ-axis direction and R-axis direction with one testing light beam.

In the conveying mechanism in which a rotary base 49 is provided on a mover moving in the horizontal direction, the rotary base is provided with two arm mechanisms 50A, 52A, and a pick is fitted to tip of each arm mechanism to convey a body to be processed, the reference position correction device includes: a light emitting part 66 for emitting a testing light beam in the horizontal direction intersecting the moving horizontal direction of the mover; a light receiving part 68 for receiving the testing light beam; a light switching part 70 for switching the testing light beam between transmission of light and interception of light; and a correction means for correcting the respective reference positions to the horizontal direction, the turning direction, the vertical direction and bending and stretching direction on the basis of the detection result of the light receiving part to the testing light beam.