A device for detecting electric potentials of the body of a patient has measuring electrode inputs (Y1, . . . , Yn) connected with and a plurality of outputs (A1, . . . , An) via amplifiers (Op1, . . . , Opn). A summing unit (13) is connected with the outputs and outputs a mean value of the signals (E1, . . . , En) output by the amplifiers. Common mode signals are removed from the signals (E1, . . . , En) by a subtracting unit (19) which subtracts the output of the summing unit, amplified by an amplification factor (1/β), from at least a portion of the output of the subtracting unit. The output of the subtracting unit is connected with the inputs of the amplifiers. The subtracting unit amplification factor (1/β) and an amplification (β′) of the amplifiers for the output of the subtracting unit are adapted, such that the reciprocal value of the amplification factor (1/β) corresponds to the amplifiers amplification (β′).
