Abstract: A freely rotatable endless belt has a bottom face that is opposed, in the water, to an ultrasonic oscillator. A carbon fiber fabric is transferred from a supply roller to a hot roller while being given tension by means of a torque motor and a constant speed motor connected to the supply roller and the hot roller, respectively. The carbon fiber fabric moves in contact with the bottom face of the endless belt, whereby endless belt rotates in synchronism with the carbon fiber fabric. Two oblique movement correcting belts are so disposed as to be pressed against both side portions of the endless belt while gripping respective selvages of the carbon fiber fabric. Each of the two oblique movement correcting belts is connected to a variable speed motor via a uni-directional clutch that transmits a driving force only in the direction of transferring the carbon fiber fabric.