Abstract: The rocking chair comprises a base member, a seat support frame rockably mounted thereon, a seat pivoted at its front end to the support frame for limited up and down movement, the weight of a person seated on the seat lowering the seat to a lower limit position against the bias of a spring, and a two part locking device carried by the base member and by the seat and mutually engageable to lock the chair against rocking when the seat is in its upper position and clearing each other when its lower limit position. Therefore, the chair is automatically locked against rocking when a person leaves the seat.