MACHINE PROVIDED WITH LUBRICATION OIL DEGRADATION SENSOR, SPEED REDUCER FOR INDUSTRIAL ROBOT AND INDUSTRIAL ROBOT

PROBLEM TO BE SOLVED: To provide a machine capable of suppressing a deterioration in the performance of a lubrication oil degradation sensor capable of instantly identifying the kind and amount of pollutants in lubrication oil.SOLUTION: An industrial robot includes an arm 112 with a lubrication oil degradation sensor 139 installed thereon, and a support 134 movable with respect to the arm 112 to mount a cleaning member 180 thereon. The lubrication oil degradation sensor 139 includes a white LED for emitting light, an RGB sensor for detecting the color of received light, and a gap forming member with an oil gap being a gap for the immersion of lubrication oil 131a formed. The gap forming member allows the light emitted by the white LED to transmit therethrough, the oil gap is arranged on an optical path from the white LED to the RGB sensor, and the cleaning member 180 is arranged at a position where the cleaning member is brought into contact with a surface for forming the oil gap in the gap forming member when the arm 112 and the support 134 perform relative displacement.