In a digital signal magnetic recording/reproducing apparatus, input digital signals of plural channels and a recording current control signal expressing recording current values corresponding to the respective digital signals are time-division mulitplexed and transmitted into a rotary cylinder, and the digital signals and recording current control signal are separated by a circuit built in the rotary cylinder. The recording current for each of the digital signals is controlled depending on the recording current control signal. By time-division multiplexing the input digital signals of plural channels and transmitting the multiplexed signal into the rotary cylinder, the number of channels of the rotary transformer can be reduced. Further, by transmitting the recording current control signal into the rotary cylinder, the recording current of the digitally transmitted signal can be adjusted.