An undoped highly-oriented diamond film is formed on a single crystalline silicon substrate, a p-type highly-oriented diamond film is formed on the insulating diamond film. An ohmic electrode is formed on said p-type semiconducting diamond film and an ohmic electrode is also formed on a n-type .beta.-SiC layer. The highly-oriented diamond films are grown by chemical vapor deposition and at least 80% of the surface area of said diamond film consists of either (100) or (111) crystal planes, and the differences {.DELTA..alpha., .DELTA..beta., .DELTA..gamma.} of Euler angles {.alpha., .beta., .gamma.}, which represent the orientations of the crystals simultaneously satisfy the following relations: .vertline..DELTA..alpha..vertline..ltoreq.5.degree., .vertline..DELTA..beta..vertline..ltoreq.5.degree. and .vertline..DELTA..gamma..vertline.5.degree. between adjacent crystal planes. The diamond hetero-junction rectifying element thus made has a high rectification ratio and heat resistance, and is suitable for mass production at low cost and on large scale.