An exhaust gas purification apparatus for an internal combustion engine according to the present disclosure obtains an electric resistance value of the electrically heated catalyst after the lapse of a predetermined period of time which is a period of time required for condensed water adhered to the electrically heated catalyst to finish evaporating from the start of energization of the electrically heated catalyst, and calculates a heat energy shortage amount which is an amount of heat energy insufficient for raising the temperature of the electrically heated catalyst to a predetermined temperature or above, based on a difference between the electric resistance value thus obtained and a predetermined reference resistance value. Then, the exhaust gas purification apparatus supplies to the electrically heated catalyst an amount of energy required to compensate for the heat energy shortage amount.