An infrared imaging device (1, 501) comprising: a thermal image sensor (2, 502) to receive infrared light and output a signal corresponding to the infrared light; a thermal image generator (31, 531) to generate a single thermal image on a basis of the signal from the thermal image sensor (2, 502); characterized by a correction coefficient calculator to calculate, for each row of the single thermal image, a plurality of correction coefficients of a polynomial constituting a correction equation for converting pixel values of pixels included in the single thermal image into corrected pixel values in which streak noise extending in the row direction from one end to another end of the single thermal image is reduced; and a thermal image corrector to correct a thermal image generated by the thermal image generator (31, 531) by correcting each row of the thermal image using the corresponding polynomial, wherein the infrared imaging device further comprises a smoothing processor to perform, for each row, a smoothing process on the pixel values of the pixels of said row, by, for each pixel of said row, averaging the pixel value of said pixel and the pixel value or values in one or more vertically adjacent rows preceding said row, and the pixel value or values in one ore more vertically adjacent rows following said row, and wherein the correction coefficient calculator calculates the coefficients of a polynomial for each row, which converts an input pixel value to a smoothed pixel value, using a least squares method to minimize the differences between the polynomial and the coordinates of points representing input pixel values and corresponding smoothed pixel values of said row, in a two dimensional space, one axis of said space representing input pixel values, the other axis of said space representing smoothed pixel values. a thermal image sensor (2, 502) to receive infrared light and output a signal corresponding to the infrared light; a thermal image generator (31, 531) to generate a single thermal image on a basis of the signal from the thermal image sensor (2, 502); characterized by a correction coefficient calculator to calculate, for each row of the single thermal image, a plurality of correction coefficients of a polynomial constituting a correction equation for converting pixel values of pixels included in the single thermal image into corrected pixel values in which streak noise extending in the row direction from one end to another end of the single thermal image is reduced; and a thermal image corrector to correct a thermal image generated by the thermal image generator (31, 531) by correcting each row of the thermal image using the corresponding polynomial, wherein the infrared imaging device further comprises a smoothing processor to perform, for each row, a smoothing process on the pixel values of the pixels of said row, by, for each pixel of said row, averaging the pixel value of said pixel and the pixel value or values in one or more vertically adjacent rows preceding said row, and the pixel value or values in one ore more vertically adjacent rows following said row, and wherein the correction coefficient calculator calculates the coefficients of a polynomial for each row, which converts an input pixel value to a smoothed pixel value, using a least squares method to minimize the differences between the polynomial and the coordinates of points representing input pixel values and corresponding smoothed pixel values of said row, in a two dimensional space, one axis of said space representing input pixel values, the other axis of said space representing smoothed pixel values.