A moving object detection method according to an embodiment includes evaluating an average value (Tave), instead of a median value (T6), of pixel values (T1 to T8) at the same pixel positions across multiple superposed images. A threshold value (Tth) obtained by multiplying the average value (Tave) by a predetermined number is employed to distinguish space debris from an object which emits light at a higher luminance than the space debris. In order to detect the space debris accurately, an average value (Tave') of the pixel values (T1 to T4 and T6 to T8) that are equal to or less than the threshold (Tth) is employed as an evaluation value for the space debris detection.