To provide a levee widening/raising construction method for achieving excellent transportation property and construction property and creating satisfactory environment by use of a steel framework member and materials obtained at site such as stones, gravel, sediment, etc. without performing the work for placing concrete requiring chipping and use of a form.

Anchor bolts 2 are driven into a side face 1a and an upper face 1b of the concrete wall 1 for retaining earth, respectively. Next, steel box-shaped forms 3 for levee widening are put in parallel on the side face 1a of the concrete wall and are fixed on the anchor bolts 2, and then their inside parts are filled with a stuffing material 7. The procedures of the work are repeated to perform levee widening of the whole side face 1a of the concrete wall. Next, steel box-shaped forms 4 for raising are put in parallel on the upper face 1b of the concrete wall positioned on an upper face of a levee widening part and behind it and are fixed on the anchor bolts, and then their inside parts are filled with the stuffing material 7, thereby performing raising of the upper face 1b of the concrete wall.