A pallet main body is provided with a block holding member which presses a positioning surface of an actuator block against a block reference surface formed in the pallet main body, and a movable arm. An insertion member, which can be inserted between a plurality of opposing suspensions, is formed at a distal end of the movable arm. As a suspension to which a slider is to be attached contacts a first contact surface formed on the side in contact with this suspension, a distal end of the suspension to which the slider is to be attached is held at a prescribed height from the block reference surface, thereby forming a gap between this suspension and a suspension opposed to this suspension.