A combination weighing device includes: an electroconductive plate opposed, with an interval, to an electroconductive part enabling detection of water intrusion inside the combination weighing device; a voltage wire for application of voltage to the electroconductive plate; and a detector that detects a potential difference between the electroconductive part and the electroconductive plate, wherein the detector or a controller of the combination weighing device determines presence or absence of water intrusion inside the interval, based on the detected potential difference.