A recognition dictionary creating device includes a user dictionary in which a phoneme label string of an inputted voice is registered and an interlanguage acoustic data mapping table in which a correspondence between phoneme labels in different languages is defined, and refers to the interlanguage acoustic data mapping table to convert the phoneme label string registered in the user dictionary and expressed in a language set at the time of creating the user dictionary into a phoneme label string expressed in another language which the recognition dictionary creating device has switched.