Provided is a semiconductor device capable of increasing the number of signals. A semiconductor device according to an embodiment of the invention includes memories; a controller that designates addresses of the memories; a mounting board having lines formed thereon, the lines connecting the controller with the memories; and a first ball group that connects the controller with the lines of the mounting board. A plurality of address lines formed on the mounting board includes an address line formed of a front surface wiring layer, and an address line formed of a back surface wiring layer. In each of the front surface wiring layer and the back surface wiring layer, each of the address lines from first balls of the first ball group is routed in order from a first memory to a fourth memory.