Pathological changes due to electrical or classic burn injuries are known mainly by autopsy to identify the cause of death. It is known that changes such as nuclear elongation and palisading appear in electrical lesions and intraepidermal separation is most frequent in electric burn lesions. Our case showed typical histopathologic changes of erythema ab igne by electrical heater. A 62-year-old woman presented with erythematous pruritic annular papules on the both forearms, which developed six month ago. Skin biopsy was performed in forearm lesions. Histopathology revealed elongated cytoplasmic processes extending into the vesicular space from the detached basal cells with elongation of basal and epithelial cell nuclei. Pathologic findings were indicative of electrical or classic burn injuries. Additional history taking revealed that lesions occurred at similar times in the abdomen. The lesion of the abdomen was clinically diagnosed as erythema ab igne. The patient has been using an electrical heater on the abdomen for 6 months. Therefore, the patient's lesions were likely to be caused by the same electrical heater, although the types were different. Use of electrical heater was discontinued and topical calcineurin inhibitor treatment was performed. Herein, we report a case of erythema ab igne by electrical heater highlighting a typical histopathological clue of electric burn.