An oiling device, used for oiling the outer wall of an inflated sausage casing pipe, and comprising a plurality of circular oiling rollers (1), an oiling material layer, and a roller retaining device. The circular oiling roller (1) is in the shape of a waist drum which is thin in the middle and thick at both ends, and is capable of freely rotating around a center rotation axis; each circular oiling roller (1) is provided with a hollow oil injection hole on the center rotation axis; one end of the oil injection hole is closed, and the other end of the oil injection hole is communicated with an oil inlet pipe (4) by means of a rotary connector (3); a plurality of micropores (5) communicated with the oil injection hole are uniformly and peripherally distributed on the outer wall of each circular oiling roller (1). The oiling material layer is made of an oil adsorbing and spreading material and is wrapped around the outer wall of the circular oiling roller (1). The roller retaining device is designed to be suitable for pressing the circular oiling rollers (1) against the outer wall of the inflated sausage casing pipe. The quantity and outer wall profiles of the circular oiling rollers (1) are designed to enable the sausage casing pipe to correspond to at least one circular oiling roller (1) at any arc on the periphery of the cross section of the outer wall.