Abstract: A method and apparatus is provided for protecting against lightning. An atmospheric potential tapping member is disposed for this purpose in the atmospheric field prone to lightning to collect a voltage (U.sub.c) which, before there is a real threat of the lightning striking, has a value which remains within a lower voltage range (U.sub.b) a capacitor is progressively charged with the voltage U.sub.c and a few tens of microseconds before there is a real threat of the lightning striking a given place, the atmospheric field will undergo a sudden increase and will therefore influence, relatively in the same way, the voltage collected which will rise up to and into a range (U.sub.h) of voltages greater than that (U.sub.b) where it was situated up to then. This potential gradient is detected with respect to time, and the evolution of the potential gradient (dv/dt) detected with respect to time is monitored in this upper range (U.sub.h) of voltages.