A resin composition contains a polymer whose enthalpy of fusion (ΔH) observed within a temperature range of 10° C. or higher and lower than 60° C. in differential scanning calorimetry is 30 J/g or more; and a low-molecular-weight compound whose enthalpy of fusion (ΔH) observed within a temperature range of 0° C. or higher and lower than 100° C. in differential scanning calorimetry is 30 J/g or more and whose molecular weight is 2000 or lower. A content of the low-molecular-weight compound is 3 parts by weight to 1000 parts by weight with respect to 100 parts by weight of the total amount of polymer components contained in the resin composition except the low-molecular-weight compound.