Substrate treatment apparatus and substrate treatment method satisfactorily applying a treatment liquid to a substrate to which a floating force is imparted and then conveyed

An object of this invention is to provide a technique for satisfactorily applying a treatment liquid to a substrate to which a floating force is imparted and then conveyed. A coating device 1 of this invention includes: a floating stage 3 for applying floating force to a substrate W; a conveying mechanism 5 for moving the substrate W provided with the floating force in a first direction D1; a nozzle 61 for discharging the treatment liquid toward the upper surface Wf of the floating substrate; a measuring device 70 for measuring the vertical position of the upper surface Wf of the substrate W; and a moving mechanism 63 for moving the measuring device 70 and the nozzle 61. The moving mechanism 63 moves the nozzle 61 and the measuring device 70 at a horizontal position (attachment horizontal position) where the treatment liquid from the nozzle 61 attaches to the substrate W approaches the horizontal position (measurement horizontal position XM1) of the area where the measuring device 70 measures the vertical pos