A coating apparatus includes a liquid film forming mechanism configured to form a liquid film of a process liquid for preventing a contaminant derived from a coating liquid from being deposited or left on a back side peripheral portion of a substrate. The liquid film forming mechanism includes a counter face portion facing the back side peripheral portion of the substrate and a process liquid supply portion for supplying the process liquid onto the counter face portion. The coating apparatus further includes a posture regulating mechanism disposed around the substrate holding member and configured to damp a vertical wobble of the peripheral portion of the substrate being rotated. The posture regulating mechanism includes delivery holes arrayed in a rotational direction of the substrate and configured to deliver a gas onto a back side region of the substrate on an inner side of the peripheral portion.