The present invention suggests a target detecting apparatus and method using a radar which detect a target using a recursive modified cell average-constant false alarm rate (RMCA-CFAR) detector without having a sorting process. The present invention provides a target detecting apparatus using a radar, the apparatus including: a data selecting unit which compares reference data with at least one of previous data and subsequent data which are located at both sides of the reference data, from a received signal including information on a distance and a speed for multiple targets, to select specific data; a cell average calculating unit which calculates an average of cells extracted using a sliding window including the specific data; a CFAR data detecting unit which detects CFAR data based on the average of the extracted cells; and a target detecting unit which detects the target based on the CFAR data.