An information generating program causing a computer to execute: obtaining a word appearance frequency information related to an appearance frequency of each word belonging to a basic word group, and a single character appearance frequency information related to an appearance frequency of each single character belonging to a designated single character group, wherein the appearance frequency of each word or each single character indicates an appearance frequency thereof in an object file group; extracting a plurality of specific words from the basic word group based on the word appearance frequency information, wherein the specific words are words ranked up to a given appearance rate among the words belonging to the basic word group and sorted in descending order of the appearance frequency; extracting a plurality of specific single characters from the designated single character group based on the single character appearance frequency information, wherein the specific single characters are single characters ranked up to a given appearance rate among the single characters belonging to the designated single character group and sorted in descending order of the appearance frequency; dividing a character code of each single character that is included in the designated single character group but not included in the specific single characters, into upper bits of a divided character code and lower bits of the divided character code; and generating for the object file group: first index information indicating for each file the presence/absence of each specific word, second index information indicating for each file the presence/absence of each specific single character, third index information indicating for each file the presence/absence of each single character including the upper bits of the divided character code, fourth index information indicating for each file the presence/absence of each single character including the lower bits of the divided character code, and fifth index information indicating for each file the presence/absence of each multi-character string that is a combination of the specific single character and the divided single character. obtaining a word appearance frequency information related to an appearance frequency of each word belonging to a basic word group, and a single character appearance frequency information related to an appearance frequency of each single character belonging to a designated single character group, wherein the appearance frequency of each word or each single character indicates an appearance frequency thereof in an object file group; extracting a plurality of specific words from the basic word group based on the word appearance frequency information, wherein the specific words are words ranked up to a given appearance rate among the words belonging to the basic word group and sorted in descending order of the appearance frequency; extracting a plurality of specific single characters from the designated single character group based on the single character appearance frequency information, wherein the specific single characters are single characters ranked up to a given appearance rate among the single characters belonging to the designated single character group and sorted in descending order of the appearance frequency; dividing a character code of each single character that is included in the designated single character group but not included in the specific single characters, into upper bits of a divided character code and lower bits of the divided character code; and generating for the object file group: first index information indicating for each file the presence/absence of each specific word, second index information indicating for each file the presence/absence of each specific single character, third index information indicating for each file the presence/absence of each single character including the upper bits of the divided character code, fourth index information indicating for each file the presence/absence of each single character including the lower bits of the divided character code, and fifth index information indicating for each file the presence/absence of each multi-character string that is a combination of the specific single character and the divided single character. first index information indicating for each file the presence/absence of each specific word, second index information indicating for each file the presence/absence of each specific single character, third index information indicating for each file the presence/absence of each single character including the upper bits of the divided character code, fourth index information indicating for each file the presence/absence of each single character including the lower bits of the divided character code, and fifth index information indicating for each file the presence/absence of each multi-character string that is a combination of the specific single character and the divided single character.