This letter describes which carrier type (electrons or holes) is dominant for EuGa2S4 thin film electroluminescent (TFEL) excitation. The transient EL wave form was measured on the EuGa2S4 TFEL devices having a single insulating thin film, which emit pure green EL due to the 5d–4f transition of Eu2+ ions. An asymmetric EL wave form was observed under a rectangular applied voltage. The EL occurs at the positively biased side of the EuGa2S4 thin film. This indicates that the green EL occurs because of hot hole excitation. Hot electrons are known to be dominant carriers to excite the luminescent centers in TFEL devices. Hot holes are also effective carriers for TFEL excitation.