To provide a block for a road enabling to construct the road with an overhanging board rigidly in a short construction term and to provide the road and a road widening method by use of this block.

This block 11 for road is provided with a bottom board 12, an inclined overhanging wall 13, the overhanging board 14, and an inclined rear surface wall 15 which are integrally formed by precast concrete and is provided with a ditch 16. A road shoulder side edge part of an existing road 51 is excavated, the block 11 for road is put on foundation concrete 32, a plurality of blocks 11 for road are arranged in parallel in the direction of road length, and counterconcrete 37 is placed in the ditch 16 at site to form a roadbed 5 on it.