A multiple joint robot includes a wrist part provided with a reduction gear unit capable of receiving an end effector and of transmitting power to the end effector. The reduction gear unit includes a fixed part fixed to the wrist part by means of a fixing element, a rotational part rotatable relative to the fixed part, and a sealing element provided in a circumference of the rotational part. There is a cover at the fixed part of the reduction gear unit, and the fixing element and the sealing element are covered by the cover. The cover is provided to flatten a convex portion or a concave portion formed by the fixing element.