The blaze started in the 13-story building at 2:54 a.m. local time (2:54 p.m. ET) in Kaohsiung city's Yancheng district, Taiwan's official Central News Agency (CNA) reported.
More than 300 workers are taking part in rescue operations, the local fire department said.
The video shown on Taiwan's local media outlets showed flames and smoke billowing out of the floors of the building while firefighters were trying to put out the fire, spraying water at it from the street.