1. A speech-to-text system comprising: a speech recognition unit which performs speech recognition of speech data and outputs a recognition result sub-word string as a sub-word string including time information based on a playback time of the speech data; a text editor unit which creates edit result text which is text information written-out from the speech data; a sub-word conversion unit which converts the edit result text into an edit result sub-word string; and a matching unit which adds the time information to an edited part in the edit result text by collating the edit result sub-word string with the recognition result sub-word string to which the time information has been added according to consistency of sub-words to thereby match the edit result text and the speech data.