An autonomous navigation method is a method of causing a mobile body (100) to autonomously navigate while comparing environmental magnetism data obtained in advance by measuring magnetism generated along a navigation path on which the mobile body (100) navigates and measured magnetism detected by actually measuring the magnetism generated along the navigation path when the mobile body (100) navigates along the navigation path. The method includes a step (a) of detecting first measured magnetism and second measured magnetism in different positions on the mobile body (100) and a step (b) of causing the mobile body (100) to autonomously navigate on the basis of the second measured magnetism detected by a magnetism sensor (103), which is not affected by unexpected magnetism (G) not included in the environmental magnetism data, and the environmental magnetism data.