On the basis of the fundamental equation of the specific interfacial energy gamma formulated in the preceding part 1 (J. Colloid Interface Sci. 1996, 181, 259; 1996, 183, 299), individual concrete equations of gamma for different interfaces in liquid-liquid, solid-liquid, solid-gas, and liquid-gas systems under the influence of adsorption have been derived, according to the inherent natures of these interfaces. For liquid-liquid and liquid-gas systems, the essential difference in behavior of ordinary adsorptives and amphiphilic compounds is discussed in detail. For solid-liquid and solid-gas systems, homogeneous and heterogeneous solid surfaces are newly defined and treated distinctively. For solid-gas and liquid-gas systems, in particular, a new concept of vacancies as imaginary matrix molecules of the gas phases is introduced to deal with these specific interfaces in the same way as the other kinds of interfaces on the basis of the fundamental equation. Lastly, the limitations of the original Langmuir and Szyszkowski equations and some basic problems of conventional thermodynamics in itself are discussed. As a result, it has been disclosed that all kinds of interfacial energies can be described in consistency as a function of the individual behavior of the interfacial molecules on the basis of the new fundamental equation and that the difference in molecular size and shape of each component in a given system is a dominant factor in the characteristic behavior of the interfacial energies of different interfaces.