An object retrieval apparatus includes a storage and a retrieval. The storage stores first to N-th space index information relating to X1 objects to XN objects which are selected in a descending order of an object size from among a plurality of objects, and in which a value of XT (where T is a value from 1 to N) decreases as a value of T increases. The retrieval processor divides a sight range into a plurality of pieces according to distance from a sight point, assign a different one of the first to N-th space index information to each divided range such that a smaller index number of the space index information is assigned to the divided range closer to the sight point, and specifies an object having a size visible from the sight point among objects existing in each divided range by retrieving the assigned space index information.