To provide a bump key exclusively for opening a cylinder lock being easily manufactured by cutting a machinable raw material by the largest depth or more corresponding to a lower pin used in a cylinder by using an exclusive blank key or a genuine key or the machinable raw material such as plastic without requiring a special tool and capable of transmitting collision energy to an upper pin efficiently to repel the upper pin by giving the collision energy to each of lower pins all at once in its use for the cylinder lock by use of the pins and rotating an inner cylinder by making a shear line between the inner cylinder and an outer cylinder free instantaneously to open the lock.

In this cylinder lock by use of pins, a part or all the parts of a plate-like material having a shape insertable into the cylinder are cut by leaving a required shape to let a borderline between the longest lower pin provided in the inner cylinder and the upper pin opposing to it agree with at least the shear line between the inner cylinder and the outer cylinder in all the sections where each of the lower pins provided in the inner cylinder of the cylinder is positioned.