The present invention proposes a liquid chromatographmass spectrometer constructed so that only necessary data are efficiently collected, and that the apparent dynamic range andor the operational condition of the MS part is appropriately changed according to the concentrations andor the qualitative information of the sample components coming from the LC part. For each desired mapping connection in a received list of desired connections, a determination of an enterprise system field and legacy system field to be mapped, as well as a connection nesting level, is made. The dynamic damper is disposed by utilizing a space between the housing and the internal mechanism so that the damping direction of the dynamic damper faces the longitudinal direction of the tool bit.