The theory of electrostatic (or, more accurately, slow electric or quasi-electrostatic) waves propagation in 1-D magnetized plasma periodic structures, at frequencies below both the plasma and cyclotron frequencies, is presented using the transfer matrix method. It assumes that the applied static magnetic field is perpendicular to the surface of the plasma layers. The dispersion relation of the waves is obtained and it is shown to break up into bands of allowed and forbidden propagation, which are conspicuous in periodic structures. Furthermore, the transmittance behavior of the electrostatic waves as a function of frequency is studied. At a fixed value of the wavenumber, the frequency range of forbidden band gaps is found to become smaller by increasing the plasma width, while the forbidden band gaps become broader as external magnetic field increases.