A signal detection device according to the embodiment of the present invention includes a memory and processing circuitry. The memory is configured to store a program. The processing circuitry is for executing the program and is configured to calculate a first signal level indicative of a signal level of a digital complex signal; calculate a first variation indicative of a temporal variation of the first signal level; calculate a statistic in a predetermined first time period on the basis of the first variation within the first time period; and determine, on the basis of the statistic in the first time period, whether or not an interference source signal indicative of a signal of a radio wave coming from an interference source is included in the digital complex signals within the first time period.