A purpose of the present invention is to improve the oil removal rate in an oil separator that separates and removes oil from gas including the oil as an impurity. The oil separator according to the present invention is characterized by including a first filter member (42) in a cylindrical shape made with a cylindrical filter material having an air permeability, and positioned such that the target gas flows in from a hollow part as well as a central axis is in an up-down direction, and a second filter member (43) made with a filter material having air permeability and wrapped around the first filter member (42) along an outer surface thereof with a predetermined spacing from the outer surface of the first filter member (42).