Improved multipolar model of photon bremsstrahlung accompanying α-decay is presented. A special emphasis is given to the development of an angular formalism of matrix elements. The model gives values of the angular probability of the emission of photons in the absolute scale, without its normalization on experimental data. Spectra calculated on the basis of the model are found in a good agreement with the newest experimental data for the 210Po, 214Po, and 226Ra nuclei. A unified formula for the bremsstrahlung, probability during the α-decay of an arbitrary nucleus, defined directly on Qα-value and numbers Ad, Zd of nucleons and protons of this nucleus, has been constructed for the first time. Inside the region of the α-decaying nuclei from 106Te up to nucleus with Ap = 266 and Zp = 109 at energy of the photons emitted from 50 keV up to 900 keV a good coincidence has been achieved between the spectra obtained by the multipolar model (where duration of calculations for one selected nucleus is up to 1 day), and the spectra obtained by the unified formula (where duration of calculations is about some seconds, using the same computer). Pacs: 23.60.+e, 41.60.-m, 23.20.Js, 03.65.Xp, 27.80.+w