The blaze was reported at 12:25 a.m. at the single-story building on the 16700 block of South Bellflower Boulevard.
When crews arrived, flames were shooting through the roof, but they were able to put out the fire in about an hour. Flames did not spread to neighboring buildings.
Arson investigators were called to the scene to figure out the cause of the fire.
City News Service contributed to this report.