PURPOSE: To provide the fitting construction of a wall panel and a floor panel in which the position of the wall panel against the floor panel can be adjusted by placing the lower face of a wall frame body on the side edge part of the upper face of a floor panel, and providing a spacer between the extending part of an outer facing material and the side of the floor panel.

CONSTITUTION: A spacer 3 is fitted to the side of a floor panel 2, and a wall frame body 11 is placed on the side edge part of the upper face of the floor panel 2 so as to position the outer face of the frame body 11 outward from the side of the floor panel. Next, under the condition in which the spacer 3 is sandwiched between the extending part 121 of an outer facing material 12 and the side of a frame body 21 with no gap, the frame body and the floor panel 2 are fixed together by driving nails 41, nails 42 are driven so as to penetrate the extending part 121, the spacer 3, and the frame body 21 and fix them, and an inner facing material 13 is stuck and fixed on the inner face of the frame body Because a wall panel 1 is positioned outward by the thickness of the spacer 3, the position of the wall panel 1 against the floor panel 3 can be adjusted by adjusting the thickness of the spacer 3.