Disclosed is an auto-folder type cellular phone capable of opening and closing the folder automatically. Particularly, the present invention relates to an auto-folder type cellular phone with a variable opening and closing velocity, which enables a user to vary a driving voltage of the cellular phone whenever desired, whereby the user, unlike a conventional auto-folder type cellular phone having a fixed (or constant) driving voltage, now can open or close the cellular phone more quickly or slowly anyway he/she wants.