The three-dimensional geometry of an attachment is measured before work is started. A maximum dimension of a take-out head 60 in the X direction, a maximum dimension of the take-out head 60 in the Y direction, and a maximum dimension of the take-out head 60 in the Z direction are measured on the basis of an image of the take-out head 60 captured by at least imaging devices C11 and C12 before the take-out head 60 starts work with the take-out head 60 being mounted to an elevating frame 59B of an apparatus 5 for taking out a molded product, as an orthogonal three-axis robot.