1. An information management method to be executed by a computer, the information management method comprising: accepting a registration request including values for latitude, longitude, and correspondence information corresponding to a place indicated by the latitude and the longitude; generating a character string as a key by alternately arraying one latitude character of latitude character string and one longitude character of longitude character string, the latitude character string and the longitude character string generated based on the latitude and the longitude, and the one latitude character and the one longitude character corresponding to a same digit position of at least two digits of the latitude and the longitude; dividing a position range corresponding to the latitude and the longitude into a plurality of increment regions according to precision of the values for the latitude and the longitude when the registration request has been received; generating, for the position range, a first group of a latitude minimum value and a longitude minimum value for the plurality of increment regions, wherein the generating of the character string as the key generates the key for the latitude and longitude minimum values included in the first group; and storing the correspondence information in a storage unit in a manner correlated with the key and storing the key in a manner correlated with the latitude and longitude minimum values in the first group, to thereby in response to a search request, execute a search for the stored key which is searchable for the correspondence information.