Ribbon cassette including ink ribbon, first spool, and second spool

A ribbon cassette includes a case, an ink ribbon, a first spool, a second spool, a rotating member, a clutch spring, and an engaging part. The ink ribbon has one end portion wound over the first spool and another end portion connected to the second spool. The rotating member is engaged with a first inner surface of the first spool. The clutch spring includes a coil like annular part attached to the rotating member, and an extension part extending from the annular part. The engaging part is positioned on a locus of rotation of the extension part. The first spool has a protrusion provided at a second inner surface of the first spool. The case-hole is in communication with an interior of the first spool, and has a portion overlapped with an entire circular region surrounded by a path of rotation of the tip end of the protrusion.