A critical small angle polarized neutron scattering experiment on invar Fe₆₅Ni₃₅ alloy was performed in the magnetic field H of value from 10 to 1000 G using a special 'inclined' geometry (H is inclined to the wave vector k). Two contributions to the critical scattering were studied in the temperature range T_C ± 0.1 T_C: first, the two-spin correlation function with its amplitude and the correlation length R_C(T, H) and, second, the three-spin dynamical spin-correlation function, by extracting an asymmetric part of the polarization-dependent scattering. The data are interpreted in terms of static and dynamic scaling theory.