As lands are becoming limited from time to time, apartments have become one of the solutions to accommodate residential and commercial purposes. The land where the apartment is built would be called mutual-land. Ownership of the mutual-land would be proved with the issuance of a deed of the land under the name of the developer, and proportionally distributed with deeds of each apartment unit under the name of the apartment unit owners. One of the correlations between the two deeds is that the validity time of the deed of the apartment units would depend on the approved validity time of the certain status of the mutual-land, which is reflected inside the deed of the land. By the time the apartment units are being bought by the future owners as written in the deed of the apartment units, the developer would gradually lose their rights in the apartment. Conveyance for the apartment units is clearly regulated, while the conveyance of the mutual-land, which is written in the deed of the land, does not have a clear regulation yet. Necessity of conveying the mutual-land is especially highlighted in order to sustain the further existence of apartment, which makes the background of extending validity period of the mutual-land. The mutual-land which has not been conveyed, would impact the extension of it since the application would need the competent subject to do so and receive the deed after its application of extension is approved. Therefore, this thesis is conducted to analyze on the conveyance and extension of the mutual-land in apartment.