In a multi-radar system, configured comprising a plurality of radar units which generate and output signals the frequency of which increases and decreases periodically, each radar unit generates and outputs signals synchronized with a prescribed sync signal, such that the upper limit and lower limit of the periodically increasing and decreasing frequency is different for the signals of each radar unit, and moreover the timing of the upper limit and lower limit of the signals substantially coincide. By this means, the frequency intervals between signals can be reduced, and more channels can be set, without causing radio wave interference.