There is provided a resin composition. A resin composition includes: a copolymer having structural units of the following Formula (1), Formula (2) and Formula (3): where X is a C1-5 alkyl group, a C5-6 cycloalkyl group, a phenyl group or a benzyl group, while the alkyl group, the cycloalkyl group, the phenyl group and the benzyl group optionally have a portion or all of the hydrogen atoms substituted with halogen atoms, carboxy groups, hydroxy groups, amino groups or nitro groups; each of R1s is independently a hydrogen atom or a methyl group; R2 is a single bond or a C1-5 alkylene group; R3 is a blocked isocyanate group; Y is an —O— group or an —NH— group; R4 is a single bond or a C1-5 alkylene group; and R5 is a C1-20 hydrocarbon group or a phenyl group having a hydroxy group as a substituent; and a solvent.