A foreign matter removing apparatus for removing foreign matter from a surface of a substrate. The apparatus is provided with: a substrate rotating mechanism which holds and rotates the substrate; and a fluid mixture supplying mechanism which generates a fluid mixture by mixing a treatment liquid and a gas, and supplies the fluid mixture onto the surface of the substrate held by the substrate rotating mechanism. The treatment liquid may be deionized water or a resist removing liquid. Examples of the foreign matter to be removed include a resist film formed on the substrate and a residue remaining on the surface of the substrate after ashing of the resist film.