  The first principles momentum dependent local ansatz wavefunction method
(MLA) has been extended to the ferromagnetic state by introducing
spin-dependent variational parameters. The theory is applied to the
ferromagnetic Fe, Co, and Ni. It is shown that the MLA yields the
magnetizations being comparable to the results obtained by the GGA (generalized
gradient approximation) in the density functional theory. The projected
momentum distribution functions as well as the mass enhancement factors are
also calculated on the same footing, and are compared with those in the
paramagnetic state. It is shown that the calculated mass enhancement factor of
Fe is strongly suppressed by the spin polarization due to exchange splitting of
the e${}_{\rm g}$ flat bands, while those of Co and Ni remain unchanged by the
polarization. These results are shown to be consistent with the experimental
results obtained from the low-temperature specific heats.
