To provide a mug cup painting method which is easy and can be performed by general consumers themselves.

This mug cup painting method comprises a pre-treatment step wherein after coating a surface coating agent which is a mixture of a resin and a hardening agent, on the surface of a mug cup, and a specified period of time has passed, by the hardening of the resin by the hardening agent, a rigid and smooth surface coat is formed on the surface of the mug cup, a step wherein a mixed coloring agent is formed by mixing a wax, a resin, an oil and a pigment, and a pattern of the mixed coloring agent is formed on the surface of the mug cup, a step wherein the mug cup is heat-treated at a specified treatment temperature for a specified period of time, and the resin of the mixed coloring agent is bonded to the resin of the surface coat, and a step wherein the mug cup is cooled to a specified temperature, and the remaining mixed coloring agent is removed from the surface of the mug cup.