Police said the paramilitary ranger patrol from Ranger Forces Regiment 47 were on duty providing security to the public in Kabang district.
As they walked along Bundang Dama-Ban Nibong Road, a bomb hidden at the roadside exploded, wounding ranger.
Identified as Chokanand Limkhew, the victim was injured on his right leg and was sent to hospital.
In nearby Narathiwat, Ranger Forces Regiment 45 launched air and land operations in Tanyong Limo sub-district of Ra-ngae district to pressure insurgents in the area.
Checkpoints were set up at all routes to the village while sniffer dogs were used to detect firearms or explosives that may have been hidden in vehicles.
The search was conducted in response to information that three leading members of an insurgent group were prepared to launch a violent attack.
The air operation was aimed to monitor the movement of suspected insurgents and survey the landscape of the district.
It was believed that the three unidentified men are still hiding in the area.