PROBLEM TO BE SOLVED: To provide a biological information detection system capable of reducing the effect of ambient light. SOLUTION: A biological information detection system 1 includes measurement devices 13 that are arranged in a steering wheel 11 and acquire biological signals from a vehicle driver 5, and a controller 25 that analyzes the acquired biological signals to generate biological information. The measurement devices 13 is provided with a pulse wave sensor 35 comprising an illuminator 31 and a detector 33, both being arranged adjacent to each other. The illuminator 31 irradiates with light a hand or a finger of a subject holding the steering wheel 11. The detector 33 receives light irradiated from the illuminator 31 and reflecting on the hand or the finger, and acquires a light reception signal to output it to the controller 25. The controller 25 checks the position of the pulse wave sensor 35 varying according to the rotation of the steering wheel 11, and generates the biological information based on the light reception signal from the pulse wave sensor 35 positioned below a predetermined horizontal plane. COPYRIGHT: (C)2012,JPO&INPIT