A portable electronic device includes a cover member, a keypad and a decorative member. The cover member defines a keypad mounting cavity. The keypad includes an annular protrusion protruding from a periphery thereof. The keypad is mounted in the keypad mounting cavity of the cover member. The decorative member includes a resisting board protruding from a peripheral wall thereof. The decorative member is sandwiched between the cover member and the keypad, with the resisting board resisting an interior surface of the cover member and the annular protrusion abutting against the resisting board, thus preventing impurities from entering into the portable electronic device via the keypad.