PROBLEM TO BE SOLVED: To detect a light signal which is projected by a floodlight only when a mobile body invades a detection range, onto which light is projected by the floodlight, from a specified direction, in a light-receiver provided in the mobile body.SOLUTION: An invasion area detection system 10 comprises: a mobile body 20 provided with a light-receiver 24 which can travel and detects a light signal； and a mobile body connector 30 constituted to be attachable to and detachable from the mobile body 20 and provided with a floodlight 32 which projects a light signal to the light-receiver 24. The light-receiver 24 is equipped with a plurality of light-receiving parts 25 in a fan-shaped manner. The floodlight 32 is equipped with a plurality of light projection parts 33 projecting light signals of different kinds, each light projection parts 33 forming a pair with each of the light-receiving parts 25. The light-receiving parts 25 detect the light signal only when a detection area is invaded from a specified direction by the light signal projected by each of the light projection parts 33, thus detecting that the mobile body 20 invades the detection range specified by the light projection parts 33.【課題】移動体に備える受光機において、投光機の投光する検出範囲に特定の方向から侵入した時のみ投光部の投光する光信号を検出させることを目的とする。【解決手段】走行が可能で光信号を検出する受光機２４を備える移動体２０と、移動体２０と脱着可能に構成され受光機２４に光信号を投光する投光機３２を備える移動体連結装置３０とで構成される侵入エリア検出システム１０であって、受光機２４は、光信号を検出する複数の受光部２５を扇状に備え、投光機３２は、各受光部２４と対になっており異なる種類の光信号を扇状に投光する投光部３３を複数備え、受光部２５は、各投光部３３が光信号を投光することで特定する検出範囲に特定の方向から検出範囲に侵入した時のみ光信号を検出し、移動体２０が投光部３３が特定する検出範囲に侵入したことを検出することを特徴とする。【選択図】図３
