The 15-kilogramme bomb was placed in a gas cylinder and triggered by a mobile phone signal when 15 soldiers were on patrol in Takbai district.
All of them were safe, but a military jeep was damaged by the explosion. The bomb caused an 80 cm wide crater on the road.
It is believed that the bombing was the work of suspected insurgents.
In a development of a shooting in Pattani, the police officer who had been attacked by gunmen armed with AK-47 rifles was pronounced dead at the hospital.
Pol Sen Sgt Maj Abdulrorsa Yuso, 44, was attacked by gunmen on motorcycles while he was about to leave home to work in Yarang district Sunday morning.
Doctors said the bullets hit vital organs, and he succumbed to the wounds.
Relatives retrieved his body from the hospital to perform Islamic funeral rites Sunday evening.