PURPOSE: To obtain a satisfied stereophonic feeling by taking a difference between both left and right channel of sound input signals after the phase of both signals is deviated.

CONSTITUTION: The equipment is provided with a 1st adder 15 adding an intermediate output signal from a 1st phase shifter 13 and an inverted intermediate output signal from a 2nd phase shifter 14, a 2nd adder 16 adding the 1st sound input signal to an output from the 1st adder 15 and a 3rd adder 17 adding a 2nd sound input signal to an output from the 1st adder 15. Then the result of addition of the intermediate output signals from the 1st and 2nd phase shifters 13, 14 at the 1st adder 15 is added to the initial sound input signal at the 2nd and 3rd adders 16, 17 and an output from the 2nd adder 16 is used as a 1st channel sound output signal and the output from the 3rd adder 17 is used as a 2nd channel sound output signal to obtain a stereo sound output. Thus, a satisfied stereophonic feeling is obtained with a simple constitution.