Abstract: A dielectric thin film device is constructed by a dielectric thin film using lead erbium zirconate titanate represented by (Pb.sub.1-y Er.sub.y) (Zr.sub.x Ti.sub.1-x)O.sub.3 with 0<x<1 and 0<y<1. This dielectric thin film element has excellent electric characteristics of a leak electric current and fatigue characteristics, etc. The dielectric thin film element may have a thermally grown silicon dioxide film, a titanium film, a platinum lower electrode, a film of lead erbium zirconate titanate represented by (Pb.sub.1-y Er.sub.y) (Zr.sub.x Ti.sub.1-x)O.sub.3 and a platinum upper electrode. These films and electrodes are sequentially formed on an n-type silicon substrate. In this case, 0.45.ltoreq.x.ltoreq.0.75 and 0.05.ltoreq.y.ltoreq.0.1 are set. A method for manufacturing a dielectric thin film has the steps of coating a substrate with a precursor solution of erbium lead zirconate titanate represented by (Pb.sub.1-y Er.sub.y) (Zr.sub.x Ti.sub.1-x)O.sub.