Distance measuring device and radio communication system

In order to measure, from the moving body side, the distance from a moving body to a predetermined stop position, this distance measuring device provided in the moving body to measure the distance between the moving body and a stop position at which the moving body should stop as a moving body/stop position distance is provided with: a storage unit that stores first reflector interval information representing the distance between a first reflector and a second reflector; a radio transmission/reception unit that transmits an electromagnetic wave the frequency of which varies continuously with a predetermined cycle as a transmission wave, and receives waves reflected from the first reflector and the second reflector; and a control unit that calculates the moving body/stop position distance on the basis of a difference frequency, which is a difference in frequency between the transmission wave and each reflected wave, using the first reflector interval information.