The old mayor's office, where Seoul's history and records reside, is a re-creation of the former Seoul City Hall's mayor’s office, reception room, and planning room. This space served as the office for successive Seoul mayors for over 60 years, from liberation until May 2008.
Successive Seoul mayors handled important office tasks, while the reception room welcomed external visitors to Seoul City Hall.
The planning room served as the core of Seoul city governance, where the mayor, city officials, experts, and citizens reported, deliberated, and made decisions on various issues. Formerly situated at the eastern end of the 3rd floor of the old city hall, it has been relocated and recreated within the secretary's office space. Visitors can now immerse themselves in viewing administrative artifacts, including the mayor's desk, chair, and gifts received from external visitors during that period.