Abstract: A bridging fault which has occurred between clock signal lines in a semiconductor device can be easily detected. A semiconductor device having a plurality of hold circuits and configured such that a scan test can be performed includes a first and a second clock signal lines supplied with normal operational clock signals having at least either frequencies or phases different from each other during normal operation, and a test clock signal controller which switches, during a test, between a state in which a first test clock signal, which is the same as that supplied to the first clock signal line, is supplied to the second clock signal line, and a state in which a second test clock signal, which is inverted or phase-shifted relative to the first test clock signal, is supplied to the second clock signal line.