A Defence Ministry spokesman said the 22-year-old sergeant, identified only by his surname Yim, shot himself in the side of his abdomen but failed to kill himself. He said Yim has been taken to a nearby hospital.
A massive manhunt was launched for Yim after authorities said he killed five comrades and injured seven others near the North Korean border on Saturday night before fleeing his frontline army unit with his standard issue K2 assault rifle.
He fired on the troops chasing him on Sunday, injuring a platoon leader.
Yesterday, officials said a South Korean soldier was wounded by suspected friendly fire.
Troops had surrounded Yim in a forest about four miles from the border outpost and threw him a mobile phone so he could talk to his father.
Yim's parents also used a loudspeaker to try to persuade him to surrender.
It was not clear what triggered the rampage and there was no indication that North Korea, South Korea's bitter rival, was involved.
Yim was due to complete his nearly two years of mandatory military service in September, according to defence officials.