The concentration dependence of the magnetic properties of iron alloys with 3 – 25 at.% gallium has been studied. It is shown that with increasing gallium content, saturation induction decreases monotonically, but coercive force shows a stepped increase with a jump from 85 to 135 A/m between 12 and 15 at.% Ga. The effect of annealing in a dc magnetic field (magnetic field annealing (MFA)) on the behavior of residual induction and coercive force in samples containing from 3 to 18 at.% of gallium was investigated. After the MFA, in the alloy a magnetic anisotropy is induced: magnetic hysteresis loops become narrower, the residual induction increases and the coercive force decreases. The MFA efficiency reaches a maximum when the gallium content is at 15 – 18 at.%. The features of the structural state in iron-gallium alloys and their role in the formation of the magnetic properties during annealing in the dc magnetic field are discussed.