PURPOSE: To produce a rotary cathode target having high density and capable of high speed film forming by arranging Si powder contg. a specified amt. of the phosphides of In, Zn, Sn and Ga on an undercoat formed on a cylindrical target holder and executing hot isotropic pressing.

CONSTITUTION: The surface of a cylindrical target holder 2 made of copper or the like is preferably roughened by sand blasting or the like and is thereafter applied with an undercoat. This undercoat has a thermal expansion coefficient in the middle of that of the target holder 2 and the target layer or close to that of the target layer. This target holder 2 is arranged in a capsule 1 made of stainless and provided with Al2O3 fiber paper 3 on the inside wall surface. Next, powder 4 essentially consisting of Si and contg. 0.01 to 30wt.% phosphides of In, Zn, Sn, Ga or the like or its formed body is arranged therein, and hot isotropic pressing is executed. In this way, the target layer having high adhesion and high density is formed to obtain the target for a low refractive index-oxide transparent thin film high in the degree of freedom.