To provide a louver rotating device capable of rotating louvers by an arbitrary opening, locking the same, and simplifying the rotating operation of the louvers.

In this louver rotating device wherein the plurality of louvers are arranged in parallel between door frames, central shafts of the louvers are projected into the door frames, the central shafts are fixed to one end of an arm, the other end of the arm is pivoted on connecting plates vertically installed in the door frames, and the louvers are rotated by vertical movement of the connecting plates, guide members are fixed to an indoor side of the door frames, slide members are slidably mounted in the guide members to drive the connecting plate, the louvers are connected to the slide members, and the slide members are slid.