To reduce a burden on a worker's physical strength during concrete spraying work on an inclined plane, and to enhance safety, a construction speed and construction quality.

An approximately Y-shaped backrest portion 1 is formed; a shoulder belt 2 is arranged in a V-shape on the bifurcated portion of the backrest portion 1; and a buckle 3 is provided at the end of the shoulder belt 2. The buckle 3 is provided with a shoulder portion for locking the other end of a breast belt 5, provided with a belt inserting portion 4 by folding back one end, to the buckle 3, and; a plurality of attachment belts 7 having one end provided with a buckle 6 are arranged in a perpendicular direction on the vertical portion of the approximately Y-shaped backrest portion 1; a ring 8 is provided at the lower end of the backrest portion 1; and a lower-end belt retainer 9 of the backrest portion 1 is provided.