621 new variable stars have been detected on plates obtained with the Schmidt telescopes of the Mount Palomar Observatory (1968) and of the European Southern Observatory (1976-1980). The astrometric measurements (ESO-CERN) and the photometrical ones (CDCA) which have followed the detection the variable stars (Observatoire de Lyon) have led to determine the parameters {alpha}, {delta}, l, b, R(Max), R(Min), {delta}m. So we notice that: - 379 variable stars have an amplitude of variation in magnitude between 0.5 and 2.0 (delm/N histogram). -The number of variable stars strongly decreases towards the great amplitudes. -The surface density of variable stars by square degree in this central galactic direction increases from 2 to 21 in the explored field of 5.5degx5.5deg size.