there is described an electronic still camera for converting captured optical images into electric image signals . the electronic still camera includes a memory to store an image data set of a captured image and a photographing data set including a date - and - time of either capturing the image or storing the image data set ; a detector to detect a residual storing capacity of the memory ; and an eraser to remove an unnecessary image data set . when a plurality of image data sets are stored in the memory and the residual storing capacity of the memory decreases at a level lower than a predetermined value , the unnecessary image data set is selected , based on dates - and - times included in photographing data sets each of which corresponds to each of the plurality of image data sets , so that the eraser removes the unnecessary image data set from the memory .