Within the microscopic Bogoliubov–de Gennes formalism an exact quantization condition for Andreev bound states of the ferromagnetic-superconducting hybrid systems of box geometry is derived and a semiclassical formula for the density of states is obtained. The semiclassical formula is shown to agree with the exact result, even when the exchange field h is much larger than the superconductor order parameter, provided h is small compared with the Fermi energy.