Method for cleaning paint spray gun

A method for cleaning a paint spray gun comprising a rotating atomization head that applies paint while rotating and an outer circumferential cylindrical body that covers an external side of a substantially conical part of the rotating atomization head and does not rotate,

• the method comprising:
• a cleaning liquid application step of applying cleaning liquid toward an external face of the outer circumferential cylindrical body of the paint spray gun;
• and
• a rotating atomization head rotation step of rotating the rotating atomization head to generate a swirling flow between the outer circumferential cylindrical body and the rotating atomization head,
• wherein the swirling flow generated by the rotating atomization head rotation step makes the cleaning liquid, applied by the cleaning liquid application step and having flowed down the external face of the outer circumferential cylindrical body, enter between the rotating atomization head and the outer circumferential cylindrical body from the external face through a leading end face of the outer circumferential cylindrical body.