Description: The anomalous magnetic moment of electron is calculated in the framework of the Schwinger source method from the assumption the electron and is immersed in the magnetic eld. The magnetic eld causes the modi cation of the Green function of the charged particle and therefore the modi cation of the vacuum- to-vacuum amplitude. The derived value of the anomalous magnetic moment of electron is in excelent agreement with experiment. The muon magnetic moment is discussed at the experimental and methodological basis. This article is written in the form of the pedagogical simplicity.