Tour guide Moon Min-ja, 67, died of severe burns and heart failure at Hana Hospital in Busan, the South Korean news agency Yonhap reported.
Seven of the people killed in the blaze were Japanese tourists.
Investigators told the news agency the fire appears to have started in an explosion within the range's shooting booths.
"After carrying out three extensive on-spot investigations, we believe that there was a huge blast inside the range and that it was the point of the ignition," Kim Young-shik, the chief investigator of the incident, told reporters.
But, Kim added, the exact cause of the fire remains unknown.