1. An interferometer-type radar comprising: a transmitter for transmitting a signal to a target; and a receiver having a large-diameter array antenna for receiving a reflection signal reflected from the target, wherein the transmitter has a function of outputting an FMCW signal for detecting direction and velocity of the target from a transmitting antenna, and the receiver includes: a plurality of correlation processors for performing correlation processing to receiving signals received by respective interference blocks configured such that the large-diameter array antenna is divided into a plurality of equal blocks; and a synthesizer for vector-synthesizing same signal components of signals outputted from the plurality of correlation processor.