This paper proposes a method of converting old addresses to current addresses for geocoding, with the aim of displaying on a map people who have such old addresses. Existing geocoding services often fail to handle old addresses since the names of towns, cities, or prefectures can be different from those of current addresses. To solve this geocoding problem, we focus on postal codes, extracting them from Web search result snippets using the query "prefecture name AND important place name AND postal code." The frequency of postal codes and the edit distance between the old address and the addresses obtained using the postal codes are used to judge the most suitable postal code and thus the corresponding current address. The effectiveness of the proposed method is evaluated in an experiment using a relative dataset. A prototype system was implemented in which users could display people using their birthdate and birthplace addresses on a map chronologically with an associated history chart.