To provide an assembly chair which is lightweight and compact with less components, improved in stiffness and strength and is assembled more easily.

The assembly chair, which can be disassembled/assembled, comprises a seating face made of a trimmed plate material, the first leg section and the second leg section. The first leg section is provided with an attachment groove going up from the lower part along the center line and the second leg section an attachment groove turning downward from the upper part along the center line; then, the attachment grooves of the first leg section and the second leg section are engaged and the first leg section and the second leg section can be assembled; a connecting section is formed on the top of the first leg section and the second leg section; the seating face is fitted with a corresponding connecting section; the connecting section of the first leg section and the second leg section and the connecting section of the seating face are engaged and the assembly chair enables the seating face to be assembled with the first leg section and the second leg section.