The present invention relates to a yarn clearer for a workstation of a textile machine with a cutting device for clearing out defects from a yarn as well as a cutting device for a yarn clearer which can be arranged at a workstation of a textile machine, with a housing body having a housing basic body, a housing cover which covers the housing basic body at least in sections and together with the housing basic body delimits a housing interior and a first housing opening and a cutting device with a cutting medium carrier having a cutting knife, a cutting medium drive arranged in the housing interior for adjusting the cutting medium carrier between a cutting position remote from the housing and a rest position close to the housing and a drive element connecting the cutting medium drive and the cutting medium carrier and adjustably arranged in the first housing opening. In order to provide a yarn clearer with a cutting device as well as a cutting device which ensure reliable separation of the yarn when required, there is provision for the housing body to have a bearing section for adjustably receiving the cutting medium carrier and a second housing opening adjacent to the bearing section with an opening edge extending perpendicularly to the adjustment direction of the cutting medium carrier and abutting the cutting medium carrier.