Abstract: In a charged particle-beam apparatus, a lens device includes a charged particle-beam lens defining a beam axis and having two centrally apertured lens members formed of magnetic material and axially spaced from each other to form a space therebetween, the apertures of the lens members defining a lens bore, specimen holder means extending axially into the lens bore for holding a specimen therein, a first cooling body situated in the space between the lens members in heat insulating relation to the lens members and extending about the axis in a plane substantially perpendicular to the latter, the first cooling body consisting of non-magnetic material and having a central opening at least substantially equal in diameter to the lens bore so that the first cooling body is prevented from protruding into the lens bore, the central opening being defined by an inner wall of the first cooling body extending axially between the lens members and circumferentially facing the specimen holder means, heat-conductive connecti