ARMREST

Disclosed is an armrest for a seat, which is accommodated at a lateral side of a seat cushion at a standby position and adjusted in height with respect to the seat cushion at an operation position. The armrest includes: a base disposed adjacent to the seat cushion; a first module rotatably connected to the base and configured to rotate about a first rotation axis so that a height of the first module with respect to the seat cushion is adjusted; and a second module rotatably connected to the first module and configured to rotate about a second rotation axis traversing the first rotation axis so that the second module is disposed horizontally or vertically with respect to the seat cushion.