An image forming apparatus that can read data from a storage medium having hierarchically structured directories includes a first directory and a second directory which is stored in the first directory. The apparatus includes: a display portion that displays designation information of the first directory; an operation portion configured to receive a designation of the second directory based on the first directory designation information displayed on the display portion; a display control portion that controls the display portion to display designation information of the second directory when the second directory is designated; and a printing portion that index-prints images on a print medium based on files stored in one of the first and second directories, the designation information of which is currently displayed on the display portion.