To provide a wall structure and its manufacturing method wherein a thinned wood which is generally discarded as waste is effectively utilized, and relaxation space which can be easily formed and has an odor of unseasoned wood can be readily formed in an established building in expensively.

A thinned wood 1 is divided into two parts in a length direction to form a half-split material 2, and both sides in a width direction of the half- split material 2 are cut off along a length direction of the half-split material 2 normally to a cut surface wherein the thinned wood is divided into two parts to form side face parts 2c, 2c. A continuous joining groove 2d is recessed along the length direction of the half-split material 2 onto the side face parts 2c, 2c. By using a crosspiece 3 so formed as to be fitted to the groove 2d, half-split materials 2 in perpendicular state are joined to each other horizontally to form a continuous body (a wall structure) 4.