A deposit removal method for removing deposits deposited on the surface of a pattern formed on a substrate by etching, includes an oxygen plasma treatment process for exposing the substrate to oxygen plasma while heating the substrate and a cycle treatment process for, after the oxygen plasma treatment process, repeating multiple cycles of a first period and a second period. In the first period, the substrate is exposed to a mixture of hydrogen fluoride gas and alcohol gas inside a processing chamber and the partial pressure of the alcohol gas is set to the first partial pressure. In the second period, the partial pressure of the alcohol gas is set to the second partial pressure lower than the first partial pressure by exhausting the inside of the processing chamber.