To impart high corrosion-proof durability to corrosion-proof materials even in the case of using a porous concrete, and avoid the waste of the corrosion-proof materials.

A reinforcing bar 2 is formed from a plurality of reinforcing materials 4, 5 formed by cutting steel bars plated with zinc as a corrosion-proof coating. Flame spray coatings 6 are formed on end portions and welded portions of each of the reinforcing materials 4, 5 by the flame spraying of zinc. A concrete block 1 consisting of a plurality of independent blocks 3 made of a porous concrete is constituted by using this reinforcing bar 2 as a reinforcement.