Four people were injured when the attacker drove his car onto the sidewalk. He then got out and began stabbing people nearby, injuring a further nine people.
Police said 12 of the victims had been hospitalized and that one person had been arrested.
The attack took place near the Seohyeon station in a commuter town some 20 kilometers (12.43 miles) from Seoul.
Thursday's attack follows a similar stabbing spree in the South Korean capital on July 21 that left three wounded and one dead.
South Korea is usually a relatively safe country with a murder rate of 1.3 per 100,000 people, according to official statistics. For comparison, the murder rate in the US is 7.8 per 100,000 people, according to the Centers for Disease Control and Prevention.
