An optical path control device is provided, including a fixed reflective mirror fixed on a first position at a fixed angle for an incident light to be reflected thereon, and a rotatable reflective mirror driven by a driving device and rotated on a fixed axle. A surface of the rotatable reflective mirror is perpendicular to the fixed axle. The axle is disposed at a second position so that a rotating path of the rotatable reflective mirror passes through the incident light reflected on the fixed reflective mirror. A normal line of an incident point of the rotatable reflective mirror where the incident light enters, and a normal line of an incident point of the fixed reflective mirror where the incident light enters generates a predetermined included angle.