The invention relates to an automatic pencil with a lead protection function. The automatic pencil comprises a pen holder assembly and a lead assembly arranged in the pen holder assembly. A holding sleeve held by hand during writing is arranged outside the pen holder assembly. The holding sleeve can move in the axial direction within a certain range relative to the pen holder assembly. A lead protection sleeve is arranged at the front end of the pen holder assembly. A linkage structure is arranged for the lead protection sleeve and the holding sleeve. According to the automatic pencil, the holding sleeve is made to move downwards through the writing pressure acting on the holding sleeve during writing, the lead protection sleeve can be driven to move downwards through the linkage structure, the length of the exposed part of a lead can be decreased, and the aim of protecting the lead to make the lead not prone to be broken is achieved.