A radar device derives, plurality of parameters according to a target and target detection distances, based of received signals that are acquired by receiving reflected waves, each of which is a radar transmission wave transmitted toward vicinity of an own vehicle and then reflected from the target existing in the vicinity. The radar device computes, from likelihood models in which first and second already-known correlations are modeled for each of the detection distances, an indicator based on likelihood ratios, which correspond to derived parameters and detection distances, of a stationary vehicle and upper object, in which the first already-known correlations correlate parameters and likelihoods of the stationary vehicle with each other and second already-known correlations correlate the parameters and likelihoods of the upper object with each other. The radar device performs a threshold determination on the computed indicators to determine whether the target is the stationary vehicle or upper object.