Provided is a method of forming an antifouling coating film including the steps of [1] preparing a colored antifouling paint containing a prescribed Si-containing hydrolyzable resin and a color pigment such that a coating film having a target dry film thickness T completely hides a surface of an object to be coated, the colored antifouling paint has a color difference ΔE1 between the coating film having the thickness T and a coating film having a dry film thickness of 0.8 T, at least 2.0, and preferably the colored antifouling paint has a color difference ΔE2 between the coating film having the thickness T and a coating film having a dry film thickness of 1.2 T, less than 1, and [2] coating a surface of the object with the colored antifouling paint until the surface of the object is completely hidden by the coating film formed from the colored antifouling paint.