Light interference gas detector for tunnel gas monitoring

The invention relates to the field of gas detection devices and particularly relates to a light interference type gas detector for tunnel gas monitoring. A horizontal bevel gear and a vertical bevel gear are arranged in a transmission box, the horizontal bevel gear sleeves a screw rod, a center of the circle of the vertical bevel gear is connected with a hand wheel, the horizontal bevel gear and the vertical bevel gear in the transmission box are meshed with each other, a top platform is lapped on a top of the vertical frame, and a base is arranged at a bottom end of the vertical frame. A topof the top platform is provided with the transmission box, one side of the transmission box is connected with a hand wheel, an edge of the hand wheel is horizontally welded with a handheld rod, and the screw rod extends out of the top of the transmission box. According to the invention, a handheld light interference detector is amplified and is fixed on a mechanism that can be raised and lowered,and the light interference