A semiconductor device including field insulating films and having first corner portions, provided on a P-type epitaxial growth layer; an N−-type cathode that is provided in the P-type epitaxial growth layer and is located on the inner sides of the field insulating films; and a P−-type anode that is formed on the cathode so as to be in contact with the cathode and covers the first corner portions provided on the inner sides of the field insulating films, wherein the junction between the cathode and the anode serves as a PN junction of the diode, and the PN junction is spaced apart from the first corner portions.