Recently some important results have been obtained in calculating absolute α-decay widths, the calculations having been performed in the zero range α-particle approximation. In this paper the effects of the finite size of the α-particle are considered. Two important effects have been found: (i) for the finite size calculation, the absolute α-decay widths decrease by 2-3 orders of magnitude, and (ii) the finite size effects are strongly dependent on the shell model configuration of the initial nucleus. In the framework of the superfluid model the absolute probabilities of finite size α-particle emission have been calculated for the favored α-transitions of more than 200 spherical nuclei. The theoretical α-widths turn out to be smaller than the experimental ones by a factor of 10, which is approximately constant for all the nuclei studied.