A robot includes an arm having a base end portion rotatably installed through a joint part and a tip end portion in which an output shaft is installed; and a drive mechanism arranged within the arm and configured to drive the output shaft at a reduced speed. The drive mechanism includes a motor having a motor shaft, a driving pulley attached to the motor shaft, a driven pulley attached to the output shaft, at least one intermediate pulley provided between the driving pulley and the driven pulley, and a plurality of belts for operatively interconnecting the driving pulley and the driven pulley through the intermediate pulley.