A pattern-forming method comprising, in the following order the steps: forming a film with an actinic ray-sensitive or radiation-sensitive resin composition comprising a resin which contains an acid-decomposable repeating unit and is capable of decreasing the solubility in an organic solvent by the action of an acid; exposing the film with an electron beam or an EUV ray; and developing the film with a developer containing an organic solvent, the concentration of the organic solvent in the developer being 90% by mass or more, wherein the actinic ray-sensitive or radiation-sensitive resin composition comprises: the resin containing an acid-decomposable repeating unit and being capable of decreasing the solubility in an organic solvent by the action of an acid; a compound generating an acid upon irradiation with an actinic ray or radiation; and a solvent; and resin is a resin containing a repeating unit having a lactone group, and a repeating unit represented by the following formula: wherein A represents a hydrogen atom, an alkyl group, a cycloalkyl group, a halogen atom, or a cyano group; R represents a halogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkenyl group, an aralkyl group, an alkoxy group, an alkylcarbonyloxy group, an alkylsulfonyloxy group, an alkyloxycarbonyl group or an aryloxycarbonyl group, and when two or more R's are present, each R may be the same as or different from every other R or when two or more R's are present, they may form a ring in combination with each other; a represents an integer of 1 to 3; and b represents an integer of 0 to (3-a). forming a film with an actinic ray-sensitive or radiation-sensitive resin composition comprising a resin which contains an acid-decomposable repeating unit and is capable of decreasing the solubility in an organic solvent by the action of an acid; exposing the film with an electron beam or an EUV ray; and developing the film with a developer containing an organic solvent, the concentration of the organic solvent in the developer being 90% by mass or more, wherein the actinic ray-sensitive or radiation-sensitive resin composition comprises: the resin containing an acid-decomposable repeating unit and being capable of decreasing the solubility in an organic solvent by the action of an acid; a compound generating an acid upon irradiation with an actinic ray or radiation; and a solvent; and resin is a resin containing a repeating unit having a lactone group, and a repeating unit represented by the following formula: wherein A represents a hydrogen atom, an alkyl group, a cycloalkyl group, a halogen atom, or a cyano group; R represents a halogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkenyl group, an aralkyl group, an alkoxy group, an alkylcarbonyloxy group, an alkylsulfonyloxy group, an alkyloxycarbonyl group or an aryloxycarbonyl group, and when two or more R's are present, each R may be the same as or different from every other R or when two or more R's are present, they may form a ring in combination with each other; a represents an integer of 1 to 3; and b represents an integer of 0 to (3-a). the resin containing an acid-decomposable repeating unit and being capable of decreasing the solubility in an organic solvent by the action of an acid; a compound generating an acid upon irradiation with an actinic ray or radiation; and a solvent; and A represents a hydrogen atom, an alkyl group, a cycloalkyl group, a halogen atom, or a cyano group; R represents a halogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkenyl group, an aralkyl group, an alkoxy group, an alkylcarbonyloxy group, an alkylsulfonyloxy group, an alkyloxycarbonyl group or an aryloxycarbonyl group, and when two or more R's are present, each R may be the same as or different from every other R or when two or more R's are present, they may form a ring in combination with each other; a represents an integer of 1 to 3; and b represents an integer of 0 to (3-a).