Abstract: An infrared detective element for detecting a dose of infrared rays by a change in electrical resistance of monofilaments composed mainly of silicon carbide upon infrared radiation thereto,either the monofilaments having a resistivity of 1.0.times.10.sup.5 to 1.0.times.10.sup.3 .OMEGA..cm at room temperature and a diameter of 3 to 200 .mu.m,or the monofilaments having a composition:Si: 50 to 70 wt %C: 28 to 40 wt %O: 0 to 10 wt %the balance (H and/or Ti or Zr): 0 to 10 wt %, and having a resistivity of 1.0.times.10.sup.5 to 1.0.times.10.sup.-1 .OMEGA..cm at room temperature and a diameter of 3 to 200 .mu.m,in either case, the monofilaments being arranged between electrodes without bringing them into contact with each other. The infrared detective elements of the present invention are excellent in properties, especially short response times.