To provide a block for a foundation capable of suppressing an increase in construction period and a labor for construction even when incidental facilities for road such as a pedestrian way and a deck are constructed on a road shoulder section.

This block for a foundation comprises an attaching/detaching section at the longitudinal ends to be detachable from the other block for a foundation. A support section for supporting the incidental facilities for road projects from the block in the outside direction of the road shoulder section. The block is laid down on the road shoulder section of the road.