To prevent malfunction without affecting a sensor electrode detecting an object even when potential of a circuit fluctuates.

A lighting system 100 includes: a lighting part 30 including a light source; a sensor electrode 11 whose electrostatic capacity to the detected object 9 varies when the detected object 9 approaches; a guard electrode 12 forming a capacitative coupling with the lighting part 30; an approach detecting part 20; and a lighting control part 23. The approach detecting part 20 connected to the sensor electrode 11 and the guard electrode 12 measures the electrostatic capacity value between the sensor electrode 11 and the detected object 9 to detect approach of the detected object 9, and controls the guard electrode 12 to have the same electric potential with that of the sensor electrode 11. The lighting control part 23 turns on or turns off the lighting part 30, or controls the same for dimming on the basis of a detected result of the approach detecting part 20. The guard electrode 12 is arranged at the position where the capacitative coupling of the lighting part 30 becomes larger than a parasitic capacitance of the sensor electrode 11 and the lighting part 30.