A sensor device includes: a member that has an aperture facing a target measuring position through which a target to be measured passes; a sensor that is provided in an opposing relation to the target measuring position, and that measures a physical quantity of the target at a sensor surface facing the aperture; and a moving member that reciprocates a movement in a predetermined direction, and includes: a cleaning unit that cleans the sensor surface by contacting the sensor surface while the moving member moves to at least one of an outward movement and a return reciprocal movement; an applying portion that applies to the moving member a force in one direction of the reciprocation movement; and a manipulation portion that is moved by an operator against the force applied by the applying portion in an direction opposite to that of a direction of the force.