The first cases of Trichophyton tonsurans infection outbreaks were reported in Japan beginning around the turn of the 21th century. Initial reports were of group infections among high school and college combat sports athletes. Gradually, the spread of infection to younger age groups, such as junior high school students, was confirmed. Today, T. tonsurans is considered one of the major causative organisms of tinea corporis and tinea capitis in Japan. The most common clinical manifestations of T. tonsurans infection are tinea corporis and tinea capitis. Tinea corporis can be difficult to distinguish from eczema, and most cases of tinea capitis are classified as being asymptomatic carriers. These presentations can make early diagnoses challenging. Diagnosis is often established by direct microscopic examination and fungal culture to isolate and identify the causative organism. In terms of treatment, T. tonsurans infection is primarily treated using an oral antifungal therapy.This review focuses on the status of T. tonsurans infections in Japan. T. tonsurans is an anthropophilic dermatophyte and may be difficult for the human immune system to eliminate. Hence, we must consistently keep T. tonsurans infection in mind during daily clinical practice.