An assembling structure, wherein an insert member is fixed to the outer surface of a column at a specified position, a receiving member is fixed to a support hole formed at the edge part of a structure beforehand, the portion of the column positioned above a position where the insert member is fixed is inserted, from a horizontal direction, into the receiving hole of the receiving member fitted to the edge part of the structure, and the insert member fitted to the outer surface of the column is fitted, from the lower side, to the receiving hole of the receiving member fitted to the support hole of the structure to assemble them integrally with each other. Or the insert member fitted to a panel or a column is fitted, from the lower side, to the receiving hole of the receiving member fitted to a shelf part to lock locking parts of approximately L-shape in plan view formed on the insert member to locking grooves of approximately L-shape in plan view formed in the receiving member so that the tapered surfaces of the insert member and the receiving member can be fixedly press-fitted against each other.