The tests were carried out to compare strength properties of four types of wooden chair joints ( dweljoints, mortise-tenon joints, rounded mortise-tenon joints, finger-joints ). The tree species of members were Red wood (Squoia sempervirens) and Keyaki (Zelkova serrata). The results of the tests are summarized as follows. Regardless of the kind of the tree species, as for the strength properties, finger-joints, rounded mortisetenon joints, mortise-tenon joints, dwel-joints were big in turn. But, when judging from the workability, rounded mortise-tenon joints was most recommended. Rounded mortise-tenon joints is recommended as the joint where the high strength is looked for, in the joining which used material with high density and high Young’s modulus. However, regardless of the kind of the tree species, economical dwel-joints is recommended in case of the joint below 60 kN･mm of maximum moment.