To provide the dust prevention structure of an entrance in a bus which can ensure an effective area of getting on and off in a nonstop bus and also prevent the invasion of dust in a car room.

In an entrance of a bus provided with an open/close door in which a getting on/off slope 8 continued to the passage in a car room and tip upper part are supported movable along a guide rail 19 extended along the car body front/rear direction and the center part of upper/lower end edge are provided to the tip 16a of a swing arm 16 and for reverse turning and moving between a close position staying along the tip edge 8a of a getting on/off slope 8 and a release position storing on the getting on/off slope 8 by the swing of a swing arm 16, a base end is combined to the side column of the entrance and the tip is combined to the lower edge tip of the open/close door 20 and its upper end is press-contacted to the lower end edge 20b of the open/close door 20 and its lower end is press-contacted with the tip edge 8a of the getting on/off slope 8 respectively in a closed state and also the dust prevention member 25 of an elastic material property folded in the open/close state is provided.