A passive oscillation damper (8), in particular for a switch cabinet (2), includes a supporting structure (12) having a longitudinal direction (y) and a transverse direction (x) and with a central oscillating mass (14) mounted by means of spring elements (20, 22, 24, 26) so as to be able to oscillate in the longitudinal direction (y) and in the transverse direction (x). At least one peripheral oscillating mass (40, 42) is mounted on the central oscillating mass (14) so as to be slidable in the longitudinal direction (y) and to be movable relative to the central oscillating mass (14). At least one peripheral oscillating mass (44, 46) is mounted on the central oscillating mass (14) so as to be slidable in the transverse direction (x) and to be movable relative to central oscillating mass (14).