A simple model is proposed to calculate a component of the electron-transfer reorganization energy derived from the reversible process of noncovalnt bond formation/dissociation between the reactant and hydrogen bonding donor or ligand. In the model, the reorganization of the formation/dissociation of the noncovalent-bonded complex is estimated by considering the chemical equilibrium change during the electron-transfer reaction. The effects of the hydrogen bonding and the ligand binding on the reorganization energies are calculated for the one-electron reduction processes of quinones, flavin, and the hem-fragment of cytochrome c based on the formation/dissociation constants of the noncovalent-bonded complexes in the liquid phase.