To provide a product of drainage passage for road surface capable of enhancing the drain function of rain water and further simplifying the road work.

A top surface opening O is provided, its lower portion 1b has a cross section almost U-shaped, slender toward the tip, a plurality of water passage holes 13 are formed in at least one side wall 1a, and a water passage body 1 provided with a projected portion 14 horizontally on the inner surface of both the side wall 1a and a grating 3 placed on the projected portion 14 are arranged, the top surfaces 3a of the grating 3 placed on the projected portion 14 are made almost flush with the road surface 61, and the passage body 1 is embedded to the surface layer 6 of the pavement having permeability.