A device for trapping damaging flying insects, including a device for diffusing an attractive gaseous cocktail, of which the composition is suitable for attracting insects, a suctioning device having an orifice for suctioning an air flow containing the insects attracted by the attractive cocktail diffused, a trap arranged with the suctioning device, and a chassis containing a gas source, which gas is a component of the attractive gaseous cocktail, where the optical insect counter includes a series of parallel deflectors installed through the suctioning orifice, a luminous barrier composed of a light transmitter and a light receiver being installed in each interval between said deflectors.