The fracture process of metals due to hydrogen embrittlement is described theoretically as a first-order phase transition. The fractured and unfractured phases are in equilibrium at the instant of fracture and are described by the equality of stresses and thermodynamic potentials. In the context of this approach, the dependences of the fracture stress on the molar hydrogen concentration and on the fracture deformation are calculated. The dependence on the molar hydrogen concentration turned out to be close to the power dependence, while the dependence on the fracture deformation is very close to linear. Not only the qualitative but also the quantitative correspondence of this model to the experimental results is shown.