PURPOSE: To obtain a recorder having high reliability and a long operation time by eliminating electrical induction, by allowing a light emitting device to emit light by the discharge current flowing to a lightning arrester or a protective gap.

CONSTITUTION: When a lightning arrester 1 is operated and a discharge current flows to an earth side through a light emitting device 2 classified by a current range, light emitting part corresponding to the discharge current value is operated and the light therefrom is transmitted to an optical fiber 3 and an optical trigger contact 4 is triggered to be operated. A counter 5 performs counting by the operation of said contact and, at the same time, a discharge current dividing circuit 6 is operated to divide a discharge current value range. The output of said circuit 6 comes to the input signal of a phase dividing circuit 7 to be outputted to a printing apparatus 9. A timer 8 always operates but, only when the optical trigger contact 4 was operated, said signal is outputted to the printing apparatus 9. By this method, highly reliable data can be transmitted over a long distance without receiving the effect of a high electric/magnetic field and there is no induction coming from earth and erroneous operation can be prevented.