A mounting device for absorbing vibration may include a housing, a mounting bolt having a first end portion inserted into the housing, a core supported inside the housing, an elastic member disposed between an outer surface of the core and an inner surface of the housing, and a separator having an outer surface fixed to an inner circumferential surface of the housing and configured to separate a first chamber and a second chamber in the housing, wherein the separator includes a mounting bracket having an outer surface fixed to the inner surface of the housing, and a center portion hole, and a membrane mounted to the mounting bracket and having a slit formed by being cut along a predetermined line within a region which corresponds to the center portion hole, and wherein a bridge is formed in the center portion hole of the mounting bracket.