1. An information processing apparatus comprising: an acquisition unit successively specifying fields to be processed out of a plurality of fields included in program information in electronic program guide information and acquiring a character string included in each specified field; an analysis unit analyzing the character string acquired by the acquisition unit and outputting an analysis result for dividing the character string into a plurality of units; a sequence generating unit generating, for each field, a sequence corresponding to character string lengths of the units based on the analysis result outputted by the analysis unit; a variance value calculating unit calculating, for each field, a variance value showing a degree of variance of magnitudes of values of items in the sequence; and a specifying unit specifying, for each program, a cast member field, in which cast member names are listed, out of the plurality of fields based on the variance values calculated by the variance value calculating unit.