A phase adjustment apparatus and a semiconductor test apparatus for automatically correcting irregularities of propagation delay of a transmission signal, so that the transmission signal transmitted between apparatuses while synchronized with a high-speed clock can be received at a stable optimal timing at a receiving end. The phase adjustment apparatus for transmitting a transmission signal synchronized with a clock between a first apparatus of the sending end and a second apparatus of the receiving end includes phase adjustment means used when retiming the transmission signal with the clock of the receiving end of the second apparatus. That is, the phase adjustment means corrects an unknown phase relationship between the clock of the receiving end and the transmission signal and delays the transmission signal by a specified amount for adjustment so that the signal can be received with a stable retiming condition.