An epoxy resin solution containing at least a curing agent and an epoxy resin mixed in an organic solvent, wherein the curing agent comprises an imide group-containing curing agent having 1 to 4 imide groups and 2 to 4 glycidyl group-reactive functional groups in a molecule, wherein the imide group-containing curing agent is a diimide dicarboxylic acid-based compound having a structure of following general formula: wherein in the general formula, X 1 and X 2 each independently represent a structure derived from an aromatic tricarboxylic acid anhydride component, an alicyclic tricarboxylic acid anhydride component, or an aliphatic tricarboxylic acid anhydride component; and R 1 represents a structure derived from an aromatic diamine component, an alicyclic diamine component, or an aliphatic diamine component; the aromatic tricarboxylic acid anhydride component being selected from trimellitic anhydride and 1,2,4-naphthalene tricarboxylic acid anhydride; the alicyclic tricarboxylic acid anhydride component being selected from 1,2,3-cyclohexanetricarboxylic acid anhydride and 1,2,4-cyclohexanetricarboxylic acid anhydride; the aliphatic tricarboxylic acid anhydride component being selected from 3-carboxymethyl glutaric acid anhydride, 1,2,4-butane tricarboxylic acid-1,2-anhydride, and cis-propene-1,2,3-tricarboxylic acid-1,2-anhydride; the aromatic diamine component being selected from m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminobenzanilide, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, bis(4-aminophenyl)sulfone, 9,9-bis(4-aminophenyl)fluorene, meta-xylenediamine, 4,4'-bis(3-aminophenoxy)biphenyl, 4,4'-bis(4-aminophenoxy)biphenyl and bis[4-(4-aminophenoxy)phenyl]sulfone; the alicyclic diamine component being selected from trans-1,4-cyclohexanediamine, 4,4'-methylenebis(cyclohexylamine), and 1,4-bis(aminomethyl)cyclohexane; the aliphatic diamine component being selected from hexamethylenediamine, 1,10-diaminodecane, and 1,12-diaminododecane; and wherein one or more hydrogen atoms of the aromatic tricarboxylic acid anhydride component, the alicyclic tricarboxylic acid anhydride component, the aliphatic tricarboxylic acid anhydride component, the aromatic diamine component, the alicyclic diamine component and the aliphatic diamine component may be substituted with a halogen atom. wherein the imide group-containing curing agent is a diimide dicarboxylic acid-based compound having a structure of following general formula: wherein in the general formula, X 1 and X 2 each independently represent a structure derived from an aromatic tricarboxylic acid anhydride component, an alicyclic tricarboxylic acid anhydride component, or an aliphatic tricarboxylic acid anhydride component; and R 1 represents a structure derived from an aromatic diamine component, an alicyclic diamine component, or an aliphatic diamine component; the aromatic tricarboxylic acid anhydride component being selected from trimellitic anhydride and 1,2,4-naphthalene tricarboxylic acid anhydride; the alicyclic tricarboxylic acid anhydride component being selected from 1,2,3-cyclohexanetricarboxylic acid anhydride and 1,2,4-cyclohexanetricarboxylic acid anhydride; the aliphatic tricarboxylic acid anhydride component being selected from 3-carboxymethyl glutaric acid anhydride, 1,2,4-butane tricarboxylic acid-1,2-anhydride, and cis-propene-1,2,3-tricarboxylic acid-1,2-anhydride; the aromatic diamine component being selected from m-phenylenediamine, p-phenylenediamine, 4,4'-diaminodiphenyl ether, 3,4'-diaminodiphenyl ether, 4,4'-diaminobenzanilide, 1,3-bis(4-aminophenoxy)benzene, 1,4-bis(4-aminophenoxy)benzene, 2,2-bis[4-(4-aminophenoxy)phenyl]propane, bis(4-aminophenyl)sulfone, 9,9-bis(4-aminophenyl)fluorene, meta-xylenediamine, 4,4'-bis(3-aminophenoxy)biphenyl, 4,4'-bis(4-aminophenoxy)biphenyl and bis[4-(4-aminophenoxy)phenyl]sulfone; the alicyclic diamine component being selected from trans-1,4-cyclohexanediamine, 4,4'-methylenebis(cyclohexylamine), and 1,4-bis(aminomethyl)cyclohexane; the aliphatic diamine component being selected from hexamethylenediamine, 1,10-diaminodecane, and 1,12-diaminododecane; and wherein one or more hydrogen atoms of the aromatic tricarboxylic acid anhydride component, the alicyclic tricarboxylic acid anhydride component, the aliphatic tricarboxylic acid anhydride component, the aromatic diamine component, the alicyclic diamine component and the aliphatic diamine component may be substituted with a halogen atom.