PURPOSE: To facilitate the operation control action of the unit by a constitution in which a remote control case is opened by a two-step motion, the first motion position being held by engaging members, and releasing the position retention of the remote control case with a predetermined spring force at the time of the position change.

CONSTITUTION: To directly operate the control panel 39 of the unit after pulling away a remote control 30, the bottom of the remote control case 23 which is in its first motion position, OPEN I, is pulled forwardly. Then, the engagement of engaging members is released with a predetermined spring force to further open an opening 25 by the elastic returning force of the spring so that the remote control case 23 may be rotated to its second motion position, OPEN II, to facilitate the operation of the control panel 39 of the unit. Since the remote control case 23 is held in the first motion position, OPEN I, for pulling and retracting the remote control 30, and in the second motion position, OPEN II, for the operation of the unit control panel 39 respectively, the operation of the unit control panel can be improved, and the operation control action of the unit can be facilitated under any condition.