Abstract: An apparatus for reproducing information units recorded on a recording medium in a hierarchical structure having a plurality of levels. In the hierarchical structure, the information units are divided into a plurality of groups, and the groups are respectively assigned to the levels. The apparatus includes: an input device that receives an input instruction to designate one of the information units; a number determination device that determines the number of the information units included in each group; a level determination device that determines, on the basis of a determination of the number determination device, one of the levels to be searched in order to identify the designated information unit; and a reproduction device that identifies the designated information unit by searching the level determined by the level designation device, and reproduces the identified information unit.