PURPOSE: To count up the number of killed insects based on the causal relation between the invation of insects and the generation of electric discharge by detecting a discharged current through insects by means of an electric shock insect killer provided with an electric shock grating to which a high voltage is impressed and counting up the number of times of current generation.

CONSTITUTION: In the electric shock insect killer 100, the electric shock grating 104 consisting of a pair of electrodes 102, 103 is arranged so as to surround the periphery of a fluorescent lamp 101 serving as an insect collecting lamp. A high voltage supplied from a high voltage generating transformer 105 is impressed on the grating 104. A counter 200 for counting up the number of killed insects has a current detecting part 202 and the detecting part 202 detects a current flowing into the insect killer 100. The current shows a waveform obtained by superposing discharged current through insects on the consumed current flowing into the fluorescent lamp 101. A discharge detecting part 203 detects only discharging due to insects. A discharge detecting part 203 detects only discharging due to insects. A counter 204 is counted up by the output of the detecting part 203. Thus, the number of insects is indirectly counted up by counting up the number of times of discharge.