of tool 11 to drive clamping screw 4 which leads to the tightening or releasing of hose clamp 1 is symbolized by an arrow 15 through the embodiment of a clamping screw 4 with a screw head 5 which has indentations 9 arranged radially outside a rotation axis 10 which are open radially outwards in connection with a surface of the screw head 5 arched in a convex manner a clamping screw 4 or a hose clamp 1 with a clamping screw 4 of this type is obtained which cannot be tampered with easily in this way a simple handling with a corresponding special tool 11 is ensured at the same time further variations compared to the exemplary embodiment shown are conceivable thereby for example a greater number of indentations 9 a non uniform distribution of indentations 9 over the circumference of screw head 5 and a deviating shape of indentations 9 seat 13 of tool 11 must then be embodied or formed in a corresponding manner the tool can also be embodied or formed in a multiple part manner for example the seat 13 can be embodied or formed as a slip on element bit which can be connected e g with handles but also electrically or pneumatically driven machine tools it is noted that the foregoing examples have been provided merely for the purpose of explanation and.