An adapter for mini-coaxial cable includes a cylindrical member for receiving a length of exposed insulating spacer of a mini-coaxial cable therein, and an electrically conductive insertion member for receiving a bare center conductor of the mini-coaxial cable therein so as to provide sufficient rigid support to the thin center conductor. When the adapter is inserted into a standard coaxial cable connector, the insertion member is radially compressed by the connector to thereby tightly grip the bare center conductor.