1. An apparatus for reducing image noise which reduces noise in an image, the apparatus comprising: a spatial noise reducing section that reduces noise from an input image by smoothing a pixel value in a spatial direction within a current image frame; a temporal noise reducing section that reduces noise from the input image by smoothing the pixel value in a temporal direction between the current image frame and a temporally preceding image frame; a pixel value range setting section that sets a pixel value range based on the pixel value of the input image and a pixel value of an image outputted by the spatial noise reducing section; and a range determining section that outputs: a pixel value of an image outputted by the temporal noise reducing section when the pixel value of the image outputted by the temporal noise reducing section is within the pixel value range; a maximum value of the pixel value range when the pixel value of the image outputted by the temporal noise reducing section is greater than the maximum value; and a minimum value of the pixel value range when the pixel value of the image outputted by the temporal noise reducing section is less than the minimum value.