A moving object detection method according to an embodiment includes evaluating an average value, instead of a median value, of pixel values at the same pixel positions across multiple superposed images. A threshold value obtained by multiplying the average value 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 of the pixel values that are equal to or less than the threshold is employed as an evaluation value for the space debris detection.