An operation terminal includes a communication unit; an operation terminal control unit; a plurality of on--period light-emitting units provided in a one-to-one correspondence to the control switches and controlled by the operation terminal control unit; a plurality of off-period light-emitting units provided in a one-to-one correspondence to the control switches and controlled by the operation terminal control unit to emit light when the load associated with the corresponding one of the control switches by relational data is in an off-state; and a housing. At least one half of the control switches are arranged one above another in a vertical direction and each of the on-period light-emitting units is arranged in such a fashion as to transversely interpose the corresponding one of the control switches between itself and the corresponding one of the off-period light-emitting units when seen from the front side.
