Left-right universal control head for venetian blind

A left-right universal control head for a venetian blind comprises a shell, a cavity is formed in the shell, an opening face is arranged on one side of the cavity, a step-shaped circular groove is formed in the position, on the opening face, of the shell, and a bead pulling chain wheel is coaxially arranged at the position of the circular groove. A main body of the pull bead chain wheel is a shaft barrel, division bars are arranged on the shaft barrel in a circumferential array mode, the surface of the shaft barrel is divided into bead grooves at equal intervals, the bead grooves are matched with pull beads, and limiting fans protruding in the radial direction are arranged on the positions, on the two sides of the bead grooves, of the shaft barrel. The shell is of an axisymmetric structure, and a groove used for installing the brake head in the cover shell is of a symmetric structure. By means of the shell and the pull bead chain wheel which are of a symmetrical structure, the brake head can be replaced left