We have developed an infrared image sensor based on bolometers on a plastic substrate that is potentially ultra low-cost due to its simple structure consisting of mainly organic materials. The bolometer includes a thermal isolator made of a very low thermal conductive polymer (parylene) and a newly developed, highly sensitive (TCR <−2%/K) carbon nanotube thin film thermistor. Experiment results showed that the responsivity of our sensor was 138V/W (at VB=2V) and the estimated noise equivalent temperature difference (NETD) at room temperature was 1.1K. The row-column type 64-pixel (8 × 8) array sensor was fabricated and evaluated while the image of a heat source was focused on the sensor array by a Ge lens. Utilizing the test readout circuit based on switching modules, we obtained the images of the heat source and confirmed the basic operation of IR imaging.