A semiconductor device has pads that are arranged in such a manner as to easily accept manual needles to carry out a test. This technique is applicable to carry out a test with use of a boundary scan test circuit in synchronization with a cycle time defined by a normal operation clock signal. The semiconductor device has a first pad connected to a first one of registers that form a serial scan chain, to supply test data to the registers, a second pad connected to a last one of the registers, and a third pad to supply a test clock signal to the registers. The registers are arranged in a central part of the semiconductor device, and the first to third pads are arranged at the periphery of the semiconductor device.