Three other soldiers were wounded after the army vehicle hit the explosive device about 30 kilometers west of Gao on the road to Gossi, according to a statement from the ministry of defense.
The wounded are receiving treatment in Gao, it said.
The fourth soldier died after an army vehicle came under attack today by gunmen east of Timbuktu, said resident Kamisse Dicko.
A Malian army spokesman, Col. Souleymane Dembele, confirmed that attack.
It was not immediately clear who was responsible.
A peace accord was signed between Tuareg separatists, armed militias and the government in June.