To provide a folding armchair which is stable without fear of unexpected folding when in use, and becomes compact in size by being folded up when not in use.

A first turning shaft 51 links a front leg 22 and a rear leg 21 at their upper parts to allow them to rotate to each other, and also rotatably supports the front part of an armrest 26. A third turning shaft 53 rotatably links one end of a link 27 and the middle part of the rear leg 21 to each other. A fourth turning shaft 54 rotatably links the other end of the link 27 and the middle part of a seat frame 23 to each other. When legs open, the first, third, and fourth turning shafts are positioned so that the third turning shaft 53 is positioned on the opposite side to the front leg 22 relative to a line segment 30 connecting the first turning shaft 51 and the fourth turning shaft 54.