A display switch section switches a display mode at a time of displaying inspection images stored in a storage device in which folders including a hierarchical structure are created by selecting the display mode from a predetermined display mode and a list display mode. A folder selecting section selects one folder to be an origin of list display when the list display mode is selected and a control section causes, in a list display region, each inspection image stored in each folder belonging to a folder group with the one folder as the origin to be list-displayed and causes to be displayed, in addition in the list display region, information which makes a folder in which a file of the inspection image is present and a folder in which the file of the inspection image is not present visually identifiable, in each folder belonging to the folder group.