To provide a road surface spray device using a disc spray machine for spraying sprayed materials such as aggregates or gravel having great specific gravities, onto a road surface with predetermined spray densities and uniform quality.

A road surface spray device 10 for spraying gravel 33 onto a road surface 32 with predetermined spray densities comprises: a disc spray machine 11; a moving body 12 mounted with the disc spray machine 11; a spread preventing cover body 13 supported on the moving body 12 and disposed with partitioning the front part and both side parts of the disc spray machine 11; and a spread deflector 14 protruded in a top-view approximately V-shape from a front cover part 13a of the spread preventing cover body 13 to the side of the disc spray machine 11. The spread preventing cover body 13 is provided movably forward and backward relative to the disc spray machine 11, and the spread deflector 14 is provided so that an angle θ1 between both oblique side portions 14a and 14b in the top-view V-shape is adjustable and a falling angle θ2 to the vertical direction is adjustable.