A bolometer thin film having a high temperature coefficient of resistance (|TCR|) is produced in a simple and easy production process to provide a highly sensitive infrared sensing element. The invention provides a bolometer using a thin film of an oxide represented by ZyCuOx, wherein Z is one or more alkaline earth metals, one or more rare earth element selected from yttrium and lanthanide elements, one or more elements belonging to Period 5 or Period 6 of the Periodic Table selected from bismuth, lead, thallium, mercury, and cadmium, or potassium or sodium, y is a number satisfying 0≦y≦2, and x is a number satisfying 0.5y
