FS CMa type stars are a group of Galactic objects with the B[e] phenomenon. They exhibit strong emission-line spectra and infrared excesses, which are most likely due to recently formed circumstellar dust. The group content and identification criteria were described in the first two papers of the series. In this paper we report our spectroscopic and photometric observations of the optical counterpart of IRAS 00470+6429 obtained in 2003-2008. The optical spectrum is dominated by emission lines, most of which have P Cyg type profiles. We detected significant brightness variations, which may include a regular component, and variable spectral line profiles in both shape and position. The presence of a weak LiI6708{AA} line in the spectrum suggests that the object is most likely a binary system with a B2-B3 spectral-type primary companion of a luminosity logL/L_{sun}_=3.9+/-0.3 and a late-type secondary companion. We estimate a distance toward the object to be 2.0+/-0.3kpc from the Sun.