A rotating door mechanism includes: a front door member having a door panel part having a nearly cylindrical side surface which is opened and closed on a side surface of a cabinet; a base member; and a rotating member, wherein the rotating member is rotatably mounted on the base member, the front door member is movably mounted on the rotating member from a direction of the door front side to a depth direction while the front door member is energized to the door front side, the base member is formed with a guiding part guiding the movement of the front door member, and the door panel part is slid to rotate the rotating member and the front door member is moved with movements in a front/depth direction and in the rotating direction by the rotating member and the guiding part, whereby the door panel part is opened and closed.