1. A moving object detection apparatus (i) having an imaging device for capturing multiple capture images having respectively different capture times and (ii) detecting a moving object captured in the multiple capture images, the apparatus comprising: a differential unit for generating a differential capture image that is generated as a difference between a base capture image and a previous capture image that is captured prior to capturing of the base capture image; a DCT coefficient calculation unit for calculating a two-dimensional discrete cosine transformation (DCT) coefficient by dividing the differential capture image generated by the differential unit into multiple pixel blocks having a predetermined number of pixels and by performing for each of the multiple pixel blocks a discrete cosine transformation (DCT); a DCT coefficient storage unit for accumulatively storing the two-dimensional DCT coefficient each time the two-dimensional DCT coefficient is calculated by the DCT coefficient calculation unit; a time-series vector generation unit (a) for generating a characteristic vector by arranging elements of the two-dimensional DCT coefficient stored in the DCT coefficient storage unit and (b) for generating a time-series vector for each of the pixel blocks at a same position of the differential capture image by arranging the characteristic vectors according to a time series; and a principal component analysis unit for calculating a principal component score that is calculated by operating (c) the time-series vector generated by the time-series vector generation unit on (d) a principal component vector that is generated by a principal component analysis on a sample of the time-series vector generated in a condition that the pixel blocks capture the moving object.