The invention concerns a surface-combustion gas burner comprising a combustion grate consisting of a metal sheet pierced with a series of slots. This burner is remarkable in that said metal sheet comprises a series of deflectors made in one piece with said metal sheet and protruding on the outer face of same, each deflector extending longitudinally and laterally above the entire surface of a slot, and in that each deflector comprises a guide portion for guiding the gas flow and a junction portion joining to the metal sheet, said guide portion being spaced from the metal sheet in such a way as to provide therewith at least one lateral gas ejection port, said deflectors being disposed in pairs in such a way that the lateral gas ejection ports of same face each other.