To provide a preceding-vehicle detecting apparatus, own-vehicle controlling apparatus and preceding-vehicle detecting method capable of detecting a preceding vehicle in a more reliable manner, a preceding-vehicle detecting apparatus (1) comprises: a millimeter wave radar (11); a measuring-target-point-group generating part (131) setting measuring-target points based on reflected waves, and single-connecting those measuring-target points having the same relative velocities to thereby generate measuring-target point groups, respectively; a group-relative-velocity determining part (132) extracting those measuring-target point groups which meets conditions for preceding vehicle, respectively; and a temporal continuity judging part (133) regarding those measuring-target point groups as preceding vehicles, each of which has a number of detected times equal to or larger than a prescribed value (N1).