To provide a socket holder capable of surely holding a socket in such a manner as to prevent it from coming off when the socket is fitted in the socket holder, and capable of easily switching for releasing the holding force at the time of fitting and removing the socket to and from the socket holder.

A shape of a fitting part of the socket holder with respect to the socket having a quadrangle insertion port generally used is a columnar shape, and the socket can be rotated even when the socket is fitted in the socket holder. A springy holding device is provided on the columnar part of the socket holder, and thereby the socket is rotated in the state that the socket and the socket holder are fitted to each other, and the fitting position is changed.