To prevent foreign matter from being mixed by a hollow needle 11 by drawing a broken piece of an elastic cap 4 and a plug body 62 therein, prevent leakage of the blood by manufacturing the needle tube with a relatively small outside diameter even if the hollow needle tube is made of synthetic resin for the safety of reducing a risk of erroneous puncture of a blood collecting operator and rationalize the disposal by incinerating it by eliminating use of a metal needle in a blood collecting device with the hollow needle 11 to be punctured from a central puncture part 63 of a plug body 62 of the blood collecting tube 6.

The tip of the hollow needle 11 in a blood collecting tube side covered with the elastic cap 4 is closed, a small hole 15 communicating with a needle hollow part 111 is provided in its sidewall, the tip of the hollow needle 11 is formed as the closed needle tip, the elastic cap 4 is closely stuck to the tube outside of the hollow needle 11 to liquid-tightly seal the small hole 15 and a cut or a small hole 41 is formed in the tip part of the elastic cap 4.