A sensor includes a light source to emit a pulse light, a light receiver to receive light, emitted from the light source and reflected from an object, a range information acquisition unit to calculate information of a range to the object based on light emission timing at the light source and light reception timing at the light receiver and a speed of the pulse light emitted from the light source, and a pulse controller to control a pulse pattern of the pulse light emitted from the light source based on the range information calculated by the range information acquisition unit.