To eliminate the necessity of placing a protective cap on top of a height-indicating reinforcing bar indicating the height for the upper bed when concrete placing is made on a slab.

A height-indicating reinforcing bar A is composed of an upside- down U-shaped reinforcing bar 1 and a surveying projection 2. Although the upside-down U-shaped reinforcing bar 1 is arranged, projecting beyond the height of the upper bed, cut faces of the reinforcing bar is not exposed at the upper end and therefore there is no need for protection. The upper part of the upside-down U-shaped reinforcing bar 1 is colored in yellow so that the presence of projecting reinforcing bar can be easily discerned. Then the height- indicating reinforcing bar A is arranged in a slab to be constructed, and a mark is attached by operation of surveying to the height-indicating reinforcing bar A on a position corresponding to the upper bed of concrete to be placed. Then, concrete is placed with the mark on the height-indicating reinforcing bar A as a guide.