A coating film forming method includes holding a substrate by a substrate holder; forming an air flow on a front surface of the substrate; supplying a coating liquid configured to form a coating film on the front surface; forming, after moving a covering member from a first position to a second position relatively to the substrate, the air flow in a gap formed by the covering member placed at the second position and the front surface of the substrate being rotated at a first rotation number such that a flow velocity of the air flow becomes larger than that of the air flow obtained when the covering member is placed at the first position; and rotating the substrate at a second rotation number higher than the first rotation number to adjust a film thickness distribution of the coating film by scattering the coating liquid from a peripheral portion thereof.