In a defective pixel detector 20 mounted on an imaging device 100, a pixel data acquisition module 20a successively obtains pixel data of a target pixel set as an object of defective pixel detection and pixel data of plural surrounding pixels located in a neighborhood of the target pixel. A first operation module 20b calculates absolute values of differences between pixel data of multiple specific peripheral pixels selected among the plural surrounding pixels, as first absolute values. A defective pixel criterion setting module 20c sets a defective pixel criterion, based on differences between the multiple first absolute values and a preset threshold value. A second operation module 20d calculates absolute values of differences between the pixel data of the target pixel and the pixel data the multiple specific peripheral pixels, as second absolute values. A defective pixel identification module 20e identifies whether the target pixel is a defective pixel, based on the multiple second absolute values and the set defective pixel criterion. This arrangement enables successive and accurate detection of defective pixels in the imaging process.