A multi-band antenna (1) used in an electronic device and formed of a metallic sheet by defining holes therein, including a first radiating portion (30), a second radiating portion (31), a third radiating portion (32), a ground portion (2), and a coaxial transmission line (4). The first radiating portion, the ground portion and the coaxial transmission line cooperatively form a loop antenna operated at a higher frequency band of about 5.15–5.875 GHz. The second radiating portion, the ground portion and the coaxial transmission line cooperatively form a first inverted-F antenna operated at another higher frequency band of about 5.725–5.875 GHz. The third radiating portion, the ground portion and the coaxial transmission line cooperatively form a second inverted-F antenna operated at a lower frequency band of about 2.4–2.5 GHz.