Electronic apparatus having tilting prevention structure

An electronic device comprising:

• a first housing;
• a second housing slidably coupled to the first housing;
• a flexible display, supported by the first housing and the second housing, the flexible display configured to expand and/or contract based on sliding-in or sliding-out movement of the second housing;
• and
• a driving unit assembly including:
• a rack gear configured to be coupled to the first housing;
• a pinion gear driven by being engaged with the rack gear;
• a motor driving mechanism comprising a motor coupled to the second housing and configure to rotate the pinion gear;
• a bracket surrounding a portion of the motor driving mechanism and the pinion gear and coupled to the second housing;
• and
• a rack gear case surrounding a first surface of the rack gear and both lateral surfaces of the rack gear;
• wherein the rack gear case including a plurality of bearings that are disposed towards the first surface of the rack gear and configured to guide the rack gear to make a linear reciprocating motion, and
• wherein at least one of the plurality of bearings is in contact with the rack gear.