To provide a ribbon spool that engages with the engaging member of a printing apparatus without causing play.

A spool body 10 includes a ribbon holding part that holds an ink ribbon and an engaging part 12 that is arranged in one end and equipped with a plurality of inclined grooves. The printing apparatus includes the engaging member 23 that has an engaging projection 22 to be engaged with the engaging part 12 of the spool body. Each of the grooves of an engaging part 12A has an inclined angle different from that of the side face of the engaging projection 22 to be engaged with the engaging part 12A, wherein at least one of the grooves of the engaging part 12A is configured to engage with the engaging projection 22 by coming in point contact with it at two points a and b.