An image processing device for receiving a moving picture including a time sequence of frames, the image processing device comprising: a plurality of one-dimensional low-pass filters configured to calculate respective low-pass filtered values (La-Ld) using a pixel of interest and pixels aligned in different one-dimensional directions with respect to the pixel of interest, in a processing window including a plurality of pixels centered on the pixel of interest, in a frame of interest; a peripheral low-pass filter configured to output, as a peripheral low-pass filtered value (Pf), a low-pass filtered value (Pf) obtained using the pixel of interest and neighboring pixels thereof in the processing window; a representative value calculator configured to perform filtering in a time axis direction, based on a pixel value of the pixel of interest in the frame of interest and a pixel value of a pixel in a position corresponding to the pixel of interest in at least one frame other than the frame of interest, to obtain a representative value (Pm) for the pixel of interest; a noise level detector (32, 37) configured to calculate absolute values of differences between the representative value (Pm) and each of the one-dimensionally low-pass filtered values (La-Ld) and to output, as a noise level of the pixel of interest, a minimum value among those of the calculated absolute differences that satisfy a predetermined condition; an NR coefficient generator (34, 44, 45) configured to receive the noise level and to generate a noise reduction coefficient (Kf, Kfb, Kgb) corresponding to the noise level according to a predetermined input-output characteristic; and an NR processor (36, 39) configured to use the noise reduction coefficient (Kf, Kfb, Kgb) to take a weighted sum of the pixel value of the pixel of interest and the peripheral low-pass filtered value (Pf). a plurality of one-dimensional low-pass filters configured to calculate respective low-pass filtered values (La-Ld) using a pixel of interest and pixels aligned in different one-dimensional directions with respect to the pixel of interest, in a processing window including a plurality of pixels centered on the pixel of interest, in a frame of interest; a peripheral low-pass filter configured to output, as a peripheral low-pass filtered value (Pf), a low-pass filtered value (Pf) obtained using the pixel of interest and neighboring pixels thereof in the processing window; a representative value calculator configured to perform filtering in a time axis direction, based on a pixel value of the pixel of interest in the frame of interest and a pixel value of a pixel in a position corresponding to the pixel of interest in at least one frame other than the frame of interest, to obtain a representative value (Pm) for the pixel of interest; a noise level detector (32, 37) configured to calculate absolute values of differences between the representative value (Pm) and each of the one-dimensionally low-pass filtered values (La-Ld) and to output, as a noise level of the pixel of interest, a minimum value among those of the calculated absolute differences that satisfy a predetermined condition; an NR coefficient generator (34, 44, 45) configured to receive the noise level and to generate a noise reduction coefficient (Kf, Kfb, Kgb) corresponding to the noise level according to a predetermined input-output characteristic; and an NR processor (36, 39) configured to use the noise reduction coefficient (Kf, Kfb, Kgb) to take a weighted sum of the pixel value of the pixel of interest and the peripheral low-pass filtered value (Pf).