To provide a rounded connector used for communication that could help speeding up work process, a ground unit using the same, and a cable connector to be connected to the rounded connector.

A rounded connector of the present invention comprises: a circular-shaped end face; a pair of housing holes; and a first and second positioning parts. The pair of housing holes are provided on a surface opposite to the end face and disposed so as to sandwich the center of the end face between them, viewed from the end face. The first positioning part is disposed at the center of the end face while the second positioning part is disposed at a place between the center of the end face and the end edge. According to the rounded connector of the present invention, since it is possible to mate the center of the end face with the cable connector to be connected by the first positioning part and determine the end face angle by the second positioning part, the cable connectors can be connected easily and precisely regardless of the initially mounted angle of the rounded connector, thereby contributing to the speed up of the work process.