Periodic variations observed from the Doppler data of F layer reflection during the solar eclipse day and control days are analyzed by using a numerical Fourier transform. The gravity waves of the 22-min period may be generated by the solar eclipse, although it is hard to confirm the existence of the gravity waves because the period is difficult to distinguish from the periods of the medium-scale TID's in the F region. The internal gravity waves seen to affect the electron density in the F layer.