Originally, it was mainly the Bureau of Carpentry that was in charge of the construction of temples; however, in light of the temple construction boom that arose out a growing awareness of national protection and the transfer of the capital, the position of Zojishi was established in order to avoid such work being conducted exclusively by the Bureau of Carpentry, as well as to prevent the power and interests being concentrated in their hands.
本来こうした造営は木工寮などが担当することとなっていたが、鎮護国家の高まりによって造寺が盛んになり、更に遷都なども重なって木工寮への業務の集中を避けると同時に、権力や利権の集中を防ぐことも目的であったとされている。