Abstract: A liquid chromatograph provided here is adapted to enable the lengths of tubing for connecting the respective constituent elements thereof to be minimized by making the positions of the respective constituent elements including a detector and a column movable and adjustable in order to reduce the dead volume in a liquid chromatograph system in plumbing and increase the analytical precision through prevention of diffusion of samples and rapid sending of a mixed liquid solvent. Furthermore, in order to prevent cross-contamination due to residues of samples and cleaning liquid in a flow channel of the liquid chromatograph system, an injection port in which a needle can be inserted is so provided as to communicate directly with a flow channel of an injection valve.