To provide a semiconductor element, capable of suppressing leakage current deepened by the generation of active moat, when applying an STI process.

A method for manufacturing the semiconductor element comprises the steps of forming an element-isolating film 30 by an STI (Shallow-Trench Isolation) process to obtain a microscopic element separation pitch, forming a plurality of gates 34 so as to pass through an active region 32 limited by the element isolating film, and forming a subgate 36 having a length relatively larger than the part but a boundary part on the side of a part adjacent to the boundary between the active region and the element separating film of the gate.