To provide a construction member for flooring capable of easily locating a floor in the case of construction and, at the same time, improving workability of flooring work.

In the construction member for flooring used in the case the flooring is formed in the shape of an approximately flat sheet in a construction space formed by a floor construction skeleton and a wall construction skeleton, the construction member is formed in a wedge shape having a vertical pane or an inclined plane, and it is so characterized that the floor is located in a state to fitly insert the wedge-shaped construction member between the wall construction skeleton and the outer circumference of the floor to set in the construction space. The construction member is formed in an approximately triangular-shape in a side view to provide a locating means to a part of the inclined plane, and a plurality of construction members are respectively arranged to three sides on the outer circumference opposed to the wall construction skeleton of the square floor in a plan view.