PURPOSE: To detect the moving direction of an object such as human body with a single detection element by arranging a plurality of reflectors and transmission filters to detect increase or decrease in the reflection factor or transmission factor.

CONSTITUTION: For example, an infrared sensor detection element 1 and reflectors 2a and 2b are arranged. When a human body 3 is moving in the direction X, the infrared sensor 1 initially detects radiate infrared rays reflected with the reflector 2a and then, radiate infrared rays reflected with the reflector 2b. As shown by the drawing (a), the detection pulse is larger in the latter than that in the former. When the human body 3 moves in the direction of Y, the detection pulse is similar as shown by the drawing (b). When a transmission filter is used in place of the reflector, detection can be done in the same way. Thus, one detection element is enough thereby eliminating the need for using a plurality of detection elements with strictly identical characteristics while facilitating the direction of an object moving without restriction in the manufacture.