Brush head assembly and electric toothbrush

Provided are a brush head assembly and an electric toothbrush. The brush head assembly comprises a brush head body, a linking component and a locking cylinder; wherein a component assembly cavity is arranged at the tail end of the brush head body, the linking component is installed in the component assembly cavity, and a deformable locking cylinder including a fulcrum force-receiving part and a force applying part with elastic forces at both ends is embedded; the locking cylinder makes most of the strokes of the drive shaft in the insertion process smooth and convenient, only until the two force applying parts are both in contact with the drive shaft, will force be generated to lock the drive shaft, and the locking effect achieved by this elastic force can be maintained for a long time. Thus ensuring the capabilities of torque transmission and axial retention.