Material shortage alarm device of extruder

The utility model is applicable to the technical field of extruders, and provides a material shortage alarm device for an extruder, which comprises the extruder, a hopper fixedly connected with the extruder, a box fixedly connected with the hopper, a first magnet fixedly connected with the box, a guide rod fixedly connected with the hopper, a lifting component movably connected with the guide rod, and a second magnet fixedly connected with the lifting component. The second magnet is movably connected with the guide rod, and the first magnet and the second magnet attract each other. A button is arranged on the box body and is electrically connected with an alarm; when raw materials in the hopper are continuously fed into the extruder, the liquid level in the hopper is continuously lowered, the lifting assembly descends along with the liquid level, the lifting assembly pulls the second magnet to enable the second magnet to be separated from the first magnet, the button is reset, the power source is connected, a