Abstract: A mobile device is disclosed. A battery housing cover mechanism (80) of the mobile device comprises a cover member (81), a pivot shaft module (90) having a pivot shaft (92), and a pivot shaft module support mechanism (I00). The module (90) is movably supported by the module support mechanism (I00). The pivot shaft (92) is located in the recessed section (107). When the cover member (81) is opened excessively beyond the normal open position, the module (90) is moved to pull the pivot shaft (92) out of a recessed section (107). Therefore, the pivot shaft (92) is prevented from receiving an excessive force.