Leading Vehicle Detecting Apparatus And Inter-Vehicular Control Apparatus Using Leading Vehicle Detecting Apparatus

A leading vehicle detecting apparatus and inter-vehicular control apparatus which can reduce delay in deciding accurately whether or not the own vehicle is following a particular leading vehicle are provided. The leading vehicle detecting apparatus includes: a signal acquiring section that acquires position signals outputted from a position detecting section that detects the position of the leading vehicle, and detection signals outputted from state detecting sections that detect a state of an own vehicle cruising line; a storage section storing in advance a probability map showing the probability of the own vehicle following the leading vehicle, based on distance from an expected cruising line of the own vehicle to leading vehicle the position; and a calculating section that calculates the expected cruising line based on is the detection signals, and judges whether the own vehicle is following the leading vehicle based on the expected cruising line, position signals, and probability map.