This invention has an objective of providing a biological component-measuring unit 2, a package of a biological component-measuring unit, a medical support instrument kit, and a package of a medical support instrument kit, which are capable of improving workability and enabling the clinical examiner to measure components of body fluids with hygienic operation. The biological component-measuring unit comprising a substrate detachablymountable on a medical support device proper, and fluid channels fixed to said substrate, the medical support device proper including a fluid transfer structure for making fluids in the fluid channels flow in one direction in cooperation with the fluid channels, wherein the fluid channels comprise a biological component-measuring channel which is: (1) attachable to and detachable from a body fluid-drawing channel for drawing a fluid that has been sampled through a body fluid sampler (2) capable of transferring the fluid in the biological component-measuring channel in one direction, in cooperation with the fluid transfer structure, once the substrate is mounted on the medical support device proper (3) provided with a biological component sensor for measuring a biological component included in the fluid being transferred and (4) capable of discharging the fluid as a waste liquid after the completion of the measurement of the biological component by biological component sensor.
