The present invention provides a semiconductor device and a manufacturing method thereof which can make a ground/power source potential stable without reducing the number of pins for signals. The semiconductor device includes a plurality of leads, a tab having a size smaller than a size of a semiconductor chip, suspending leads connected to the tab and having suspending lead exposing portions, four bar leads connected to the suspending leads and arranged outside the semiconductor chip, first wires for connecting pads of the semiconductor chip and the leads, second wires for connecting the pads of the semiconductor chip and the bar leads, and a sealing body for sealing the semiconductor chip using resin. On a back surface of the sealing body, a distance between the suspending lead exposing portion and the lead exposing portion is set to a value equal to or more than a distance between the lead exposing portions. Due to such a constitution, the suspending leads can be used as external terminals and hence, the ground and the power source potential can be made stable.