An object of the present invention is to provide a zirconia mill blank for dental cutting and machining which may impart high translucency similar to an enamel of a natural tooth to zirconia sintered body even in a short time sintering, and a preparing method thereof. In addition, the present invention provides a zirconia mill blank for dental cutting and machining which may impart the same degree of translucency to a zirconia sintered body even in a short time sintering as compared with the case of sintering for 427 minutes.The zirconia mill blank for dental cutting and machining of the present invention contains a gallium compound.