"Hide and Seek" is expected to hit the 3 million viewer mark just eight days after its release on Aug. 14.
According to the Korean Film Council on Thursday, 207,311 tickets for the film had been sold on Wednesday alone, catapulting it to the top spot at the box office.
It had attracted altogether 2.83 million viewers as of Wednesday.
The thriller revolves around two families who believe strangers to be living in hiding in their houses and try to fight them.
"The Flu" sold 99,650 tickets on Wednesday to rank second for the day with a total of 2.2 million viewers, and "Snowfiercer" 68,806 to rank third with 8.41 million viewers since Aug. 1.