A sensor device comprising: a movable reflection unit reflecting an electromagnetic wave toward inside a predetermined scanning range; a detection unit detecting a deflection angle of the movable reflection unit; and a receiving unit receiving the electromagnetic wave reflected or scattered by a structure positioned in the scanning range; characterized in that the sensor device further comprises an amendment unit amending a detection result by the detection unit, based on a receiving result of the electromagnetic wave by the receiving unit, the electromagnetic wave being reflected by the structure, wherein the amendment unit amends the detection result by the detection unit, based on a relation between a first receiving value of the electromagnetic wave by the receiving unit, the electromagnetic wave being reflected or scattered by a first part of the structure, and a second receiving value of the electromagnetic wave by the receiving unit, the electromagnetic wave being reflected or scattered by a second part of the structure, wherein the amendment unit amends the detection result by the detection unit, based on a comparison result between the relation between the first receiving value and the second receiving value, and a relation between a first reference receiving value of the electromagnetic wave by the receiving unit, the electromagnetic wave being reflected or scattered by the first part of the structure, when the detection unit operates in a reference state and a second reference receiving value of the electromagnetic wave by the receiving unit, the electromagnetic wave being reflected or scattered by the second part of the structure, when the detection unit operates in the reference state. a movable reflection unit reflecting an electromagnetic wave toward inside a predetermined scanning range; a detection unit detecting a deflection angle of the movable reflection unit; and a receiving unit receiving the electromagnetic wave reflected or scattered by a structure positioned in the scanning range; characterized in that the sensor device further comprises an amendment unit amending a detection result by the detection unit, based on a receiving result of the electromagnetic wave by the receiving unit, the electromagnetic wave being reflected by the structure, wherein the amendment unit amends the detection result by the detection unit, based on a relation between a first receiving value of the electromagnetic wave by the receiving unit, the electromagnetic wave being reflected or scattered by a first part of the structure, and a second receiving value of the electromagnetic wave by the receiving unit, the electromagnetic wave being reflected or scattered by a second part of the structure, wherein the amendment unit amends the detection result by the detection unit, based on a comparison result between the relation between the first receiving value and the second receiving value, and a relation between a first reference receiving value of the electromagnetic wave by the receiving unit, the electromagnetic wave being reflected or scattered by the first part of the structure, when the detection unit operates in a reference state and a second reference receiving value of the electromagnetic wave by the receiving unit, the electromagnetic wave being reflected or scattered by the second part of the structure, when the detection unit operates in the reference state. the amendment unit amends the detection result by the detection unit, based on a relation between a first receiving value of the electromagnetic wave by the receiving unit, the electromagnetic wave being reflected or scattered by a first part of the structure, and a second receiving value of the electromagnetic wave by the receiving unit, the electromagnetic wave being reflected or scattered by a second part of the structure, wherein the amendment unit amends the detection result by the detection unit, based on a comparison result between the relation between the first receiving value and the second receiving value, and a relation between a first reference receiving value of the electromagnetic wave by the receiving unit, the electromagnetic wave being reflected or scattered by the first part of the structure, when the detection unit operates in a reference state and a second reference receiving value of the electromagnetic wave by the receiving unit, the electromagnetic wave being reflected or scattered by the second part of the structure, when the detection unit operates in the reference state.