According to the source, unidentified gunmen shot the soldier while on duty in the North Sinai city of Arish.
The attackers have fled the scene unscathed.
Egyptian authorities are yet to comment on the attack.
Sinai has been the center of heightened violence against police officers and army personnel since the July 3 ouster of Egypt's first freely-elected President Mohamed Morsi at the hands of the army.
Dozens of officers and soldiers have been killed in several attacks so far.