Pin tumbler lock cylinder and key

The pin tumbler lock cylinder comprises a lock cylinder shell, a pin tumbler set, a lower lock cylinder connected to the lock cylinder shell and an upper lock cylinder rotationally connected to the lock cylinder shell, the pin tumbler set comprises an upper pin tumbler and a lower pin tumbler, the lower lock cylinder is provided with a pin tumbler groove allowing the lower pin tumbler to be arranged in a sliding mode, and a pin tumbler spring is arranged in the pin tumbler groove. The end portions of the marble springs abut against the groove bottoms of the marble grooves and the lower marbles respectively, upper marble holes are formed in the upper lock cylinder in a penetrating mode, the number of the upper marble holes is the same as that of the marble grooves, the upper marbles are arranged in the upper marble holes in a sliding mode, and the end portions of the lower marbles can stretch into the adjacent upper marble holes and abut against the adjacent upper marbles. The upper marble is characterized in