PURPOSE: To make it possible to obtain an optical thin film having stable optical characteristics by mixing lower titanium oxide having a specified molar ratio with zirconium oxide so that the molar ratio of Ti to Zr is regulated to a specified value and sintering the resulting mixture.

CONSTITUTION: Lower titanium oxide having 1.0-1.75 molar ratio of O to Ti is mixed with zirconium oxide so that the molar ratio of Ti to Zr is regulated to 0.02-0.50 and the resulting mixture is sintered to produce a material for vapor deposition. When this material is used, the amt. of gaseous oxygen released at the time of vapor deposition is reduced, so vapor deposition can be started as soon as sputtering is started and vapor deposition time per one cycle can be shortened.