Thermal-type infrared imaging device comprises an infrared ray detection unit in which pixels, each of which includes a bolometer, are arranged two-dimensionally; and a signal processing unit that sequentially reads signal of each bolometer in synchronization with switching operation of a horizontal shift register and a vertical shift register, integrates the read signal using an integration circuit, and outputs the integrated signal. The signal processing unit is configured so that it can set a sensitivity (for example, voltage applied to bolometer, capacitance of a capacitor in the integration circuit, and/or period of time for integrating the signal) for each pixel according to a predetermined pattern in synchronization with switching operation for classifying a plurality of pixels into a plurality of types of pixels for which different sensitivities are set, for example, high-sensitivity pixels 15 with a narrow temperature measurement range and a high temperature resolution and low-sensitivity pixels 16 with a wider temperature measurement range and a lower temperature resolution than those of the high-sensitivity pixels 15.