In order to ensure that a proper clustering operation is performed on measurement records of one or more radars, a processor 23 in an object detection device 3 is configured to acquire settings data for one or more radar grids 41 for measurement, each radar grid 41 being set for a measurement area 18 of a corresponding one of the radars and consisting of a plurality of radar cells R; acquiring settings data for a processing grid 45 for clustering operations, the processing grid 45 being set for the one or more measurement areas 18 and consisting of a plurality of processing cells F; calculate, for each processing cell, one or more likelihoods associated with measurements of one or more related radar cells R based on distances between the processing cell F and the one or more related radar cells R; calculate a grid value of each of the processing cells F in the processing grid 45 based on the one or more likelihoods; and perform a clustering operation on each processing cell based on (i) distances between the processing cell F and one or more different processing cells (F), and/or (ii) the grid values of the processing cell and the one or more different processing cells.