By Agence France-Presse
A 53-year-old man who said he started the blaze was arrested.
Witnesses said a delivery man carried out the attack in a fit of anger after being denied a room at the two-story motel for allegedly being drunk.
The man, identified only by his surname Yu, bought 10 litres (around two gallons) of petrol at a nearby service station, poured it on the ground floor and set it ablaze, they said.
Neighbours used fire extinguishers in an attempt to tame the blaze but were unable to bring it under control.