A breakage detection device for detecting breakage of a window glass capable of opening and closing an opening of a vehicle is provided. The breakage detection device includes a clip, a magnetic sensor, a detection unit, and a determination unit. The clip is arranged at an end portion of the window glass and holds an end portion of the window glass with a force enabling the end portion of the window glass to be crushed when the window glass breaks. The magnetic sensor detects displacement of at least part of the clip when the window glass breaks. The detection unit acquires an output value of the magnetic sensor in predetermined time intervals to detect a temporal change in the output value of the magnetic sensor. The determination unit determines that the window glass is broken when the temporal change detected by the detection unit is outside a tolerable range.