  We propose that screened pairing interactions mediated by phonons could give
rise to a spin triplet superconductivity in ferromagnetic compounds such as
UGe_2. It is pointed out that the pairing interactions include anisotropic
components such as those of p, d, f-waves in addition to dominant s-wave
component due to the momentum dependence. Since the ferromagnetic long-range
order coexists, there is a large splitting of the Fermi surfaces of up and down
spin electrons, which suppresses singlet pairing. Therefore, triplet pairing
occurs at last due to the sub-dominant anisotropic interactions, even in the
absence of magnetic contribution to the pairing interactions.
