1. An information display control apparatus comprising: a plurality of information storage units, each having stored headwords and their explanatory descriptions described in a respective one of a plurality of types of local character codes; a specifying unit for specifying any particular one of the plurality of information storage units; an input unit for inputting a retrieval word to the apparatus; a control unit for retrieving a headword corresponding to the inputted retrieval word from the particular information storage unit specified by the specifying unit and for displaying an explanatory description for the retrieved headword; a retrieval word specifying unit for specifying as a second retrieval word a word contained in the explanatory description displayed by the control unit; a first character code converting unit for converting to relevant all-purpose character codes the local character codes of the word in the particular information storage unit specified by the retrieval word specifying unit; a second character code converting unit for converting the all-purpose character codes to which the local character codes of the particular word was converted by the first character code conversion table to the corresponding local character codes of the type used in a second one of the plurality of information storage units to be retrieved; and a second control unit for retrieving from the second information storage unit a headword matching the specified word described in the type of local character codes to which the all-purpose character codes of the specified word were converted by the second character converting unit and for displaying an explanatory description on the headword.