To provide an armrest for a vehicle seat capable of avoiding an interference with a bucket of a seat cushion when a seat back is inclined forward and avoiding an interference with a console box and a hand brake, etc.

This armrest is provided with an armrest main frame 12 which is rotatably mounted on the side 44 of the seat back 42 at a root and oscillated to forward and backward inclined positions, an armrest cover frame 13 put on the armrest main frame 12 from the above and rotatably pin-connected to the tip of the armrest main frame 12 at the front end, a stopper pin 21 fixedly supported close to the tip of the armrest main frame 12, and circular-arc slots 22 fitted with the stopper pins 21 to guide the rear free end of the armrest cover frame 13 to the rear side of the seat back 42 in a state that the armrest main frame 12 is in a backward inclined position.