An air bearing includes: a main body part having a bearing surface facing a guide surface; a flow path part provided in the main body part; an air film forming part that supplies compressed air flowing through the flow path part to the guide surface to form an air film; a negative pressure generating part that sucks air between the bearing surface and the guide surface, the negative pressure generating part being provided in the flow path part; a discharge path in communication with the flow path part; and a flow rate adjusting part that adjusts a flow rate of air flowing from the flow path part to the discharge path in accordance with a compressed air pressure corresponding to a load applied to the main body part.