To provide a phase correction circuit for common mode and quadra ture signals whose phase shifting range is not affected by changes in ambient environment or aging when a phase shifting range of a transmission clock signal is set by adjusting the phase.

This circuit consists of the following devices: a digital-to-analog converter 4 for common mode signals which converts common mode signals from digital to analog signals using a leading part of a transmission clock signal (TXC.I); a digital-to-analog converter 5 for quadrature signals which converts quadrature signals from digital to analog signals using a leading part of the TXC.Q; a pulse width modulator 13 which changes the position of a trailing part of the TXC.Q; high-frequency converters 8 and 9 which convert common mode and quadrature signals which have been converted from digital to analog signals to high-frequency common mode and quadrature signals. The pulse width modulator 13 adjusts the position of the trailing part of the TXC.Q so that phase errors of the high-frequency common mode and quadrature signals are eliminated.