Provided is a tape cartridge which enables the movement of an engagement position between a ribbon feeding core and a feeding-side driving shaft to the outside in a radial direction without enlarging a ribbon winding core in the radial direction. The tape cartridge includes a ribbon feeding core (42) on which an ink ribbon (R) is wound so as to be capable of being fed, and a ribbon winding core (43) that winds the ink ribbon (R) fed from the ribbon feeding core (42). The ribbon feeding core (42) has a core body (81) that winds the ink ribbon (R), and a crown engaging part (82) that is formed at an end of the core body (81) and engages with a feeding-side driving shaft (34) of a tape printer (1). The crown engaging part (82) protrudes in an axial direction from an end surface of the core body (81) and is formed in a crown shape in which a plurality of convex parts (82a) and concave parts (82b) are alternately arranged side by side in a circumferential direction.