A kind of needle assemblies for medical device, including being suitable for receiving the needle hub of needle cannula and with the needle shield of open end. Needle assemblies are suitable for from integral type configuration change to broken configuration, in integral type configuration, needle hub is aligned with needle shield, wherein by the first end of needle hub covering needle shield, and wherein, fragility, which is connected between shield coupling part and hub coupling part, forms integral type connection, and in the broken configuration, fragility connection is broken, and thus needle hub and needle shield are the parts of two separation, and thus, it is possible to remove needle shield from needle hub.
