STRUCTURE OF SOFA

PROBLEM TO BE SOLVED: To provide a structure of a sofa which can be manufactured with a comfortable backrest for sitting in a simple structure with high accuracy and is excellent in design and good for total looking including the back face from the periphery.SOLUTION: A plurality of back plates 15 are almost vertically built up and kept apart from each other in the horizontal direction on a horizontal part 14 on the side of the back end 13 of a seat part 5. The back plate 15 includes a lower half part plate 21 which is vertical to the seating face 12 of the seat part 5 and built up on the horizontal part 14 and an upper half part 22 which is connected to the upper end of the lower half part plate 21 and inclines backward from the connection part 23. Each of the upper half part 22 and the lower half part plate 21 is formed of a board 24 which is a plain-sawn lumber following the grain lengthwise in the longitudinal direction, the connection part 23 of the upper end of the lower half part plate 21 and the lower end of the upper half part 22 are connected to each other with a finger joint at a predetermined angle and a midway part is bent in an almost dogleg shape.