A wrench includes a body and a driving head connected to the body. The body includes a push rod, two first push pieces, two second push pieces and a push unit so as to control the position and angle that the driving head rotates relative to the body. The driving head includes multiple positioning holes, an engaging protrusion, a through hole in the engaging protrusion, a bead and a control rod to control the engagement or disengagement between the engaging protrusion and the socket.