To provide a mounting structure of an interior finish board carrying out wall work excellent in sound isolation efficiency while restraining the rising of the costs.

An installation of a plaster board 16 to a wall surface 1402 is made by gypsum adhesives 20 dotted in the shape of a dumpling at a large number of spots at an interval from each other between the wall surface 1402 and the plaster board 16 and adhered to both of the wall surface 1402 and the plaster board 16 and elastic sealing compounds 22, and an air space 24 lies between the plaster board 16 and the wall surface 1402. An interval from each other between the gypsum adhesives 20 dotted in a large number of spots is set by the size larger than an interval from each other between the elastic sealing compounds 22 dotted in a large number of spots.