A method of manufacturing a semiconductor storage device having a capacitive element having a dielectric layer having a perovskite-type crystal structure represented by general formula ABO.sub.3 and a lower electrode and an upper electrode disposed so as to sandwich the dielectric layer therebetween; in the method are carried out forming, on a lower electrode conductive layer, using a MOCVD method, an initial nucleus containing at least one metallic element the same as a metallic element in the dielectric layer, forming, on the initial nucleus, using a MOCVD method, a buffer layer containing at least one metallic element the same as the metallic element contained in both the initial nucleus and the dielectric layer, in a higher content than the content of this metallic element contained in the initial nucleus, and forming, on the buffer layer, using a MOCVD method, the dielectric layer having a perovskite-type crystal structure.