A substrate treating method for removing a liquid adhering on a surface of the substrate while a pattern formed on the surface of the substrate is prevented from collapsing, comprising: a supplying step of supplying a dry assistant liquid comprising a sublimable substance in a melt state onto the pattern-formed surface of the substrate, wherein the dry assistant liquid is composed of the sublimable substance and an alcohol showing compatibility with the sublimable substance, wherein the concentration of the alcohol in the dry assistant liquid ranges from 0.001 to 0.8% by volume of the dry assistant liquid; a solidifying step of solidifying the dry assistant liquid on the pattern-formed surface to produce a solidified body; and a sublimating step of sublimating the solidified body to be removed from the pattern-formed surface; wherein the supplying step is a washing/rinsing step supplying the dry assistant liquid while adjusting the temperature of the dry assistant liquid, immediately before the dry assistant liquid is supplied to the pattern-formed surface of the substrate, to a temperature that is higher than the melting point of the sublimable substance by 10°C or more and is lower than lower one of the respective boiling points of the sublimable substance and the alcohol, and using the dry assistant liquid as a washing liquid and a rinsing liquid; and wherein the sublimable substance is a fluorinated carbon compound that is at least one selected from the group consisting of the following compounds, and having a vapor pressure of greater than 4.1 kPa at 20°C, and not containing a hydroxyl group: a compound: tetradecafluorohexane; a compound: at least one selected from the group consisting of 1,1,2,2-tetrachloro-3,3,4,4-tetrafluorocyclobutane, 1,2,3,4,5-pentafluorocyclopentane, 1,1,2,2,3,3,4-heptafluorocyclopentane, fluorocyclohexane, dodecafluorocyclohexane, 1,1,4-trifluorocyclohexane, 2-fluorocyclohexanol, 4,4-difluorocyclohexanone, and 1,2,2,3,3,4,4,5,5,6,6-undecafluoro-1-(nonafluorobutyl)cyclohexane; a compound: tetrafluorotetracyanoquinodimethane. a supplying step of supplying a dry assistant liquid comprising a sublimable substance in a melt state onto the pattern-formed surface of the substrate, wherein the dry assistant liquid is composed of the sublimable substance and an alcohol showing compatibility with the sublimable substance, wherein the concentration of the alcohol in the dry assistant liquid ranges from 0.001 to 0.8% by volume of the dry assistant liquid; a solidifying step of solidifying the dry assistant liquid on the pattern-formed surface to produce a solidified body; and a sublimating step of sublimating the solidified body to be removed from the pattern-formed surface; wherein the supplying step is a washing/rinsing step supplying the dry assistant liquid while adjusting the temperature of the dry assistant liquid, immediately before the dry assistant liquid is supplied to the pattern-formed surface of the substrate, to a temperature that is higher than the melting point of the sublimable substance by 10°C or more and is lower than lower one of the respective boiling points of the sublimable substance and the alcohol, and using the dry assistant liquid as a washing liquid and a rinsing liquid; and wherein the sublimable substance is a fluorinated carbon compound that is at least one selected from the group consisting of the following compounds, and having a vapor pressure of greater than 4.1 kPa at 20°C, and not containing a hydroxyl group: a compound: tetradecafluorohexane; a compound: at least one selected from the group consisting of 1,1,2,2-tetrachloro-3,3,4,4-tetrafluorocyclobutane, 1,2,3,4,5-pentafluorocyclopentane, 1,1,2,2,3,3,4-heptafluorocyclopentane, fluorocyclohexane, dodecafluorocyclohexane, 1,1,4-trifluorocyclohexane, 2-fluorocyclohexanol, 4,4-difluorocyclohexanone, and 1,2,2,3,3,4,4,5,5,6,6-undecafluoro-1-(nonafluorobutyl)cyclohexane; a compound: tetrafluorotetracyanoquinodimethane. a compound: tetradecafluorohexane; a compound: at least one selected from the group consisting of 1,1,2,2-tetrachloro-3,3,4,4-tetrafluorocyclobutane, 1,2,3,4,5-pentafluorocyclopentane, 1,1,2,2,3,3,4-heptafluorocyclopentane, fluorocyclohexane, dodecafluorocyclohexane, 1,1,4-trifluorocyclohexane, 2-fluorocyclohexanol, 4,4-difluorocyclohexanone, and 1,2,2,3,3,4,4,5,5,6,6-undecafluoro-1-(nonafluorobutyl)cyclohexane; a compound: tetrafluorotetracyanoquinodimethane.