An armrest according to the present invention includes a support member (8a, 215, 308a) which is a support structure, and an armrest main body (8b, 216, 308b), the armrest main body (8b, 216, 308b) includes a lower layer member (8j) including an operation lever (8p, 235, 308p) which is supported by a support member (8a, 215, 308a) to be movable in a forward-and-rearward direction and is operated by a seated person, and an upper layer member (8k) supported by the lower layer member (8j) to be movable in right-and-left direction, and the upper layer member (8k) covers the operation lever (8p, 235, 308p) at a base position in the right-and-left direction.