PROBLEM TO BE SOLVED: To provide a cleaning method of a pipeline milker, capable of improving working efficiency for collecting cleaning liquid residual water remaining in milk tubes 15 and 17, in a cleaning process of cleaning a milk pipe 30 by sucking a cleaning liquid from a milking unit 10.SOLUTION: The cleaning method of the pipeline milker involves executing the cleaning process of making the cleaning liquid flow from one end side of a milk pipe 30 to the other end side, the milk pipe 30 being encircled in a livestock barn 90 of becoming a milking site. In a stage of making the air flow in from the milking unit 10 when the cleaning liquid residual water of the cleaning process is collected, an on-off valve (a diaphragm valve 11a) arranged in a flow passage up to be connected to the milk pipe 30 from the milking unit 10 is opened and closed so as to make air intermittently flow in to the flow passage inside of continuing with the milk pipe 30 via the milk tubes 15 and 17 from the milking unit 10.
