PROBLEM TO BE SOLVED: To provide a quantitative sampling apparatus, a biological component measuring apparatus, and an artificial pancreas apparatus each of which does not require calibration even after tube replacement.SOLUTION: A quantitative sampling apparatus includes a catheter which guides a diluted biological solution prepared by diluting a biological solution with a diluting solution supplied via a diluting solution supply path to a diluted biological solution guide path. The apparatus further includes a tube pump which has a plurality of coupled moving pressure members 3a, 3b, 3c, 3d for pressing out the diluting solution and diluted biological solution by flattening and stretching out a diluting solution supply tube for supplying the diluting solution to the diluting solution supply path and a diluted biological solution guide tube for guiding the diluted biological solution supplied from the diluted biological solution guide path at the same time and a plurality of moving pressure members for the diluting solution supply tube which are supported by a rotary shaft 4 for rotating the plurality of coupled moving pressure members and disposed between the coupled moving pressure members so as to press the diluting solution supply tube.
