Abstract: A system for identifying livestock and other individuals comprising an identification plate for identifying the animal and a gate-shaped antenna, which is characterized in that the identification plate is a marker plate, which in turn is made of a soft material and comprises a flexible printed board formed with an antenna coil, a tuning condenser and an electronic circuit; said gate-shaped antenna comprises plural unit antennas which are wound with a coil each and which are crossed at an angle so that electromagnetic fields can be generated over a wide range of area without interfering with each other at the time of radio wave transmission/reception for retrieving data on said identification plate.