An object of the invention is to provide an image record apparatus and an image record method that can improve the use efficiency of a record medium for recording a video image from a camera. A NW control section (141) acquires the image quality and the resolution set in a camera (10) performing pre-record and calculates the maximum image size that can be transmitted by the camera (10), and a file system (142) calculates the number of images from the preset pre-record rate and pre-record time and reserves an area corresponding to the maximum image size of one pre-record image calculated by the NW control section (141) in an HDD (146). The NW control section (141) records a pre-record image transmitted from the camera (10) in the area reserved by the file system (142). When it records as many pre-record images as the number of pre-record images, it returns to the beginning of the area reserved by the file system (142) and continues recording a pre-record image is continued. When an alarm occurs while a pre-record image is recorded, the NW control section 141 determines that the pre-record image at the point in time is pre-record data.