The present technology is to provide a detector capable of detecting an input voltage outside the guaranteed operating voltage range, even if the delay time caused in a logic element by a decrease in power-supply voltage varies due to an external factor. The detector includes a plurality of first detection circuits, a first detection rate calculation unit, a plurality of second detection circuits, a second detection rate calculation unit, and a comparison determination unit. Each of the plurality of first detection circuits detects whether or not an input voltage has a value outside a guaranteed operating range for a normal operation. The first detection rate calculation unit calculates a first detection rate of the detected number of the first detection circuits, and each of the plurality of second detection circuits detects whether or not a predetermined reference voltage is lower than a threshold voltage.