The invention relates to a joint device which can be arranged between every two adjacent frameworks and used for enabling the adjacent frameworks to be oppositely folded or spread and positioned. The joint device comprises a male seat joint and a female seat joint that are oppositely covered, a sliding block is arranged between the male seat joint and the female seat joint in a sliding manner, anannular baffle wall is arranged on the female seat joint and provided with at least one through hole, a corresponding actuating lug boss is arranged on the sliding block, an elastic assembly is arranged between the sliding block and the inner peripheral edge of the male seat joint, when the sliding block protrudes out of the male seat joint and the female seat joint, the actuating lug boss is clamped in the through hole so as to limit that the male seat joint and the female seat joint can not relatively rotate and the frameworks are positioned in a spreading state, when the sliding block is pushed into the male seat joint and the female seat joint, the actuating lug boss is separated from the through hole so that the male seat joint and the female seat joint can relatively rotate and the frameworks are folded, therefore, residual members are not influenced by the entering sliding block and the integrity of the residual members is maintained, and the operation of a user is convenient.