To provide a small-sized hollow needle which is fixed to the front part of a mounting device and smoothly sticks out a small-sized engaging piece without hooking.

In this small-sized hollow needle, a metallic main part and a socket part are integrally formed on the outer peripheral face of a rear expansion part of this main body part with synthetic resin, a hollow hole for forwardly guiding a cross rod part of the engaging piece is opened by penetrating the center of the main part and the socket part, and a reception part for receiving the cross rod part and guiding it to the hollow hole is formed only in the socket part by cutting work.