Helium, which has been first discovered on the Sun with the help of spectral analysis, plays together with hydrogen the most important role in astrophysics. Two fundamental values are discussed: the primordial helium abundance originated as a result of the Big Bang and the current helium abundance in young near stars when they begin their evolution. It is shown that during the main sequence phase the enrichment by helium occurs in massive star atmospheres. Data on the helium enrichment of components of the close B- and O-type binaries are discussed. Stars with strong anomalies of helium and hydrogen are considered, namely: chemically peculiar Ap-and Bp-type stars with helium deficiency, as well as some types of stars with helium atmospheres.