1. An image taking system comprising an image taking means which takes an image by an image taking, an objective body detecting means which detects a predetermined objective body from the image taken by the image taking means, a storage means which stores a detection history comprising a past result of detection of the predetermined objective body and a newest result of detection of the predetermined objective body, and a determination means which refers to the detection history and determines whether the predetermined objective body is to he handled as detected in an image obtained newest, in which when the predetermined objective body has been detected not less than N times in M times results of detection including the past results of detection (M≧N), the determination means determines that the predetermined objective body is to be handled as detected in the image obtained newest.