Station keeping and attitude control are required to make a communication satellite stationary in a 24-hour orbit against various perturbations. An electrical micro-thruster is considered to be more suitable for a long life operation because the exhaust velocity of propellant easily reaches about 100 times higher than that in the cold gas jets and so the propellantconsumption becomes negligible. This paper deals with preliminary experiments on an electron-bombardment-type ion engine and represents some available informations for designing future engines. The magnetic field has been found to be efficient not only for the ionization of propellant but for the ion extraction from the ionization chamber of the engine. Plasma boundaries in the ionization chamber seem to change positions depending on the intensity of the magnetic field. The influence of the teststand pressure and the effect of the neutralizer are discussed in detail.