The invention relates to a rotary evaporator comprising a rotary drive and a fastening device attached to the rotary drive and having a receiving space for receiving an evaporator flask rotatable by the rotary drive, wherein the fastening device comprises a connector section, in particular a ring-shaped connector section, at the rotary drive side and a retainer element, in particular a ring-shaped retainer element, at the evaporator flask side that coupled to the connector section and that is rotatable relative to the connector section between a starting position and an end position. The fastening device comprises at least one clamping element that is moved, on the rotation of the retainer element relative to the connector section from the starting position into the end position, from a release position radially inwardly into a holding position in which the respective clamping element projects into the receiving space to hold a flange-shaped connection region of an evaporator flask received in the receiving space of the fastening device in a form-fitting and/or force-fitting manner and to secure it against a removal from the receiving space.