Cutaneous mucormycosis (CM) is a rare opportunistic fungal infection caused by the order Mucorales, which associated with trauma, burns and surgical wounds. A 84-year-old male visited our clinic complaining of black necrotic ulcer with erythematous halo on right lateral shin since 2 weeks ago. The patient had medical history of hypertension and pityriasis lichenoides et varioliformis acuta (PLEVA) treated with 200mg/day of doxycycline. Physical examination revealed multiple, 1 to 3cm-sized, irregularly shaped ulcers with black eschar and peripheral erythematous halo simulating an ecthyma gangrenosum were on right shin, where the skin lesion of PLEVA was located. He denied any history of trauma on the lesion. He had no systemic symptoms. Skin biopsies were conducted from center and margin of the lesion, showed necrosis and inflammatory cell infiltration in the dermis to subcutaneous layer, and large, non-septate, right-angled branching hyphae with positive special staining for periodic acid-Schiff and Gomori methenamine silver. Rhizopus species was isolated from tissue culture, which was consistent with CM. The patient was successfully treated with a combination of surgical debridement and 20mg/day of amphotericin B intravenously, and the lesion was totally reepithelialized without any evidence of eschar. We herein report a interesting and educative case of CM arising in the site of PLEVA.