A flexible socket of a power source hub is provided. The input terminal of the hub is electrically connected with a power source. The hub distributes the power source into a plurality of output terminals including first electrodes, second electrodes and ground electrodes. A plurality of sockets extend out from the output terminals via 3-strand cables. Each socket includes three holes corresponding to the first electrode, the second electrode, and the ground electrode. The three-hole sockets are designed to open in a first direction. The strands of the 3-strand cable are arranged one on top of the other in the first direction and extended outside the hub in a second direction substantially perpendicular to the first direction. In this way, it is easy to bend and displace sockets sideways to facilitate the plug-in of the plugs.