Abstract: An armrest device including a stationary shaft 2, fixed to a seat frame, an armrest body 7 in which the stationary shaft 2 is inserted and which is rotatable, a lock spring 3 made of a coil spring tightly wound around the stationary shaft 2, with one end of the coil spring serving as a stationary-side hook 3a locked to the armrest body 7, and the other end of the coil spring serving as a free-side hook 3b A hook-supporting part 12 that supports the free-side hook 3b such that the free-side hook 3b is raised in the axial direction of the stationary shaft 2, a hook-fitting part 13 that enlarges the diameter of the lock spring 3 by dropping the free-side hook 3b on the hook-supporting part 12 downward in the axial direction of the stationary shaft 2, a plate 11 for a hook, where the plate 11 projects from the armrest body 7, and a cam member 5 on the stationary shaft 2.

Abstract: An armrest includes a stationary shaft, fixed to a seat frame, the shaft is inserted and is rotatable about an armrest body, a spring wound around the shaft, one end of the spring being a stationary-side hook locked to the armrest, the other spring end being a free-side hook, a hook-supporting part supporting the free-side hook in a raised direction of the shaft, a hook-joint enlarging a spring diameter by dropping the free-side hook on the hook-supporting part downward in the axial direction of the shaft, and a cam on the shaft 2 and having an unlocking cam part for unlocking the spring by dropping the free-side hook from the hook-supporting part into the hook-joint when the armrest body is rotated, and a relocking cam part for locking the spring by raising the free-side hook from the hook-joint and supporting it by the hook-supporting part when the armrest body is rotated.