Electroresistance has become a stimulating research topic because of its potential applications in next-generation nonvolatile memory technology. Here, an electroresistance-like behavior of the antiperovskite Mn3GaC compound around the antiferromagnetic–intermediate phase transition is reported. A high sensing current significantly decreases the fraction of the antiferromagnetic phase of higher resistivity relative to the intermediate phase of lower resistivity upon warming, showing a resistivity change up to 50 %. Through extensive studies of the resistivity at different sample locations and of the magnetization under applied current, it is unambiguously shown that this electroresistance-like behavior originates from the local Joule heating of the sample due to high-resistive lead contacts and not from an intrinsic effect. These findings open an available avenue to explore electroresistance-like behavior by achieving phase coexistence of a high- and low-resistivity phase under the driving force of local Joule heating.