Arm rest device

An arm rest device comprising a mechanism for adjusting an inclined/raised angle of an arm rest body, the mechanism including a base plate structure having a proximal end portion fitted rotatably over a fixation shaft protruding laterally from one lateral end of a seat frame of a seat back, a stationary plate having a proximal end portion fitted over said fixation shaft, a Y-shaped pawl member pivotally attached to said stationary plate by a pivot shaft, a toggle spring having one end fitted into and pivotally supported by said stationary plate and the other end pivotally fitted into a support hole formed in a first end portion of said Y-shaped pawl member, and a ratchet secured to said base plate structure, said ratchet having, in a surface thereof opposed to a tooth pawl formed in a second end portion of said Y-shaped pawl member, a row of serrated teeth arranged in an aligned manner, and a protrusion in a terminal portion of said row of serrated teeth for permitting release and commencement of engagement between said tooth pawl and the row of serrated teeth.