An aluminum chelate-based latent curing agent capable of curing a thermosetting epoxy resin under the condition of relatively low temperature in a short period of time is provided. Furthermore, a method for manufacturing the latent curing agent is provided, in which the curing conditions of the aluminum chelate-based latent curing agent can be controlled relatively easily.The aluminum chelate-based latent curing agent is prepared by reacting an aluminum chelate agent with a silsesquioxane type oxetane derivative in the presence of a water insoluble or poorly water-soluble cellulose ether, whereby latency properties are imparted thereto. This latent curing agent contains a coating layer composed of the water insoluble or poorly water-soluble cellulose ether. Preferably, the surface is treated with an isocyanate compound.