The apartment was singed in a 12-square-meter area, resulting in estimated property damage of 4 million won ($3,550). However, the fire was extinguished within 10 minutes. There were no casualties.
Continuing summer heat across the peninsula is causing a series of mishaps, including power failures in areas of dense population.
Some 1,200 households in Sasang-gu, Busan, suffered a two-hour blackout in the middle of a sweltering night Sunday, due to the number of people using electricity for air conditioning and fans.
While people may have air conditioning to turn to, the scorching heat is proving even tougher on farm animals, as well as some in the sea.
Water temperatures have climbed to nearly 30 degrees Celsius in Gyeongsang regions.
According to the city government of Pohang, North Gyeongsang Province, the water temperature since Friday has hovered about 4 to 5 degrees Celsius above its on-year average. Local fish farmers have reported losses of some 48,000 fish in four days due to the overheated seas, resulting in financial losses of about 36 million won.
The National Institute of Fisheries Science extended a high water temperature advisory to South Jeolla Province on Sunday.
In South Jeolla Province as of Friday, 255 farms had reported losses of over 320,000 animals this summer. The affected animals were chickens, ducks and pigs, with the number of dead chickens at 296,000.