To provide a concrete part body of an L-shaped side ditch block for road surface drainage or the like and a road surface drainage system which properly drain the water on a road surface in rainfall, and excel in workability.

In a sidewalk/roadway boundary block 7 or the L-shaped side ditch block 6, a water collecting part body or a water collection mechanism is provided on the side neighboring a drainage pavement of the road surface. A rigid part body forming a water permeable part is the body having a rigidity such as a metal, a resin like a plastic or a ceramic.