An ink ribbon cassette is provided. A first and second ribbon-receiving parts of an ink ribbon cassette according to the invention includes wallsthat face each other with a predetermined distance therebetween. An ink ribbon slides on a first ribbon-sliding portion formed at a first wall of the first ribbon-receiving part and a second ribbon-sliding portion formed at a first wall of the second ribbon-receiving part, and is wound on a take-up reel from the feeding reel. A ribbon guide, which prevents the ink ribbon exposed at the second ribbon-sliding portion from coming in contact with a printer body (not shown) when the ink ribbon cassette is mounted in the printer body, is provided outside the second ribbon-sliding portion.