A multiband antenna used for a portable communication device includes a first antenna unit, a second antenna unit, a third antenna unit, and feed member. The first antenna unit, the second antenna unit and the third antenna unit are capable of receiving and/or sending wireless signals. The second antenna unit is connected to the first antenna unit, the third antenna unit is connected to the first antenna unit, and the feed member is electrically connected to the first antenna unit and the second antenna unit. The feed member receives wireless signals and transmits the wireless signals through the first antenna, the second antenna unit and the third antenna unit to generate corresponding current paths, and the first antenna unit is located between the second antenna unit and the third antenna unit to isolate the second antenna unit and the third antenna unit to avoid coupling interference of their resonant frequencies.