To fasten a wire bundle in a state of being positioned and fixed in a wire guide frame with a fixing band in accordance with the diameter of the wire bundle.

Wire lead-out ports are formed at sidewalls of a case body of an electric connection box, the wire guide frame is formed in an inverted U-shape at its cross-section by making an upper wall and both the sidewalls abut against each other from rims of the wire lead-out port, a through-hole is formed in the upper wall of the wire guide frame, a stepped notch is formed so as to continue stepwise along the opposing rims of the through-hole in the wire insertion direction, the fixing band is wound around the wire bundle in the wire guide frame through the lower end of either of the sidewalls and led out to the outside of the walls in accordance with the diameter of the wire bundle through the prescribed step of the stepped notch, and the wire bundle is fastened and fixed to the locking part of the fixing band.