The utility model relates to an infrared monitor for automatically putting down a rod and sending out alarm at railway crossings, which comprises a transmission mechanism composed of an electromotor, a speed reducer a rope winding roller, an upstroke roller and ropes respectively connected with a stop rod and the rope winding roller and a corresponding automatic control device composed of a logic control circuit, an infrared transmitting circuit, a receiving circuit, a decoding circuit, a memory circuit, a modulating circuit, a transmitting circuit, an alarm circuit and a wireless receiver. The utility model has the advantages of accurate automatic control, reliable performance, strong environment applicability, obvious social benefits, etc. The utility model can monitor the unidirectional and bidirectional running of trains, prevents causing traffic troubles because of the running of the trains. In the meantime, the utility model is easy to implement and is favorable to popularize and use. The utility model is especially suitable for suburb unwatched railway crossings.