The present invention relates to an oxide thin film for a bolometer-type uncooled infrared detector having high sensitivity. An amorphous vanadium tungsten oxide (V--W--O.sub.x), i.e. a tungsten-doped vanadium oxide, is provided as an oxide film for a bolometer application. An oxide for bolometer having characteristics of low resistance of 5 to 200 k .OMEGA. and variable TCR between -1.5 and -4.1%/.degree. C. can be obtained by an oxidation of vanadium-tungsten metal film at a low temperature around 300.degree. C., with changing a tungsten content and oxidation time. And a reproducible thin film can be fabricated by low price equipment for thin film deposition, without expensive ion beam or laser apparatus. Accordingly, an oxide for bolometer having characteristics of resistance lower than 100 k.OMEGA. and TCR higher than -3%/.degree. C. can be obtained with reproducibility, whereby an uncooled-type infrared detector having high sensitivity can be fabricated.