A device for measuring electromyographic signals 2 is adapted to receive, through multiple channels “C”, electromyographic signals “EMG” sensed by a plurality of electrodes 3 arranged on a patient “P”. The device 2 includes: a conditioning circuit 21 a conversion circuit 22 a transmission circuit 23 to transmit the digitalized signals to a central control unit 1 an external casing 20 to enclose the circuits (21, 22, 23). The conditioning circuit 21 can be assembled modularly by establishing a cascade connection of one or more conditioning circuits 21. The conversion circuit 22 can be assembled modularly by connecting in parallel one or more conversion circuits 22 to vary the number of channels “C” through which electromyographic signals “EMG” are received. The conditioning circuits 21 and the conversion circuits 22 overlap at least partially to limit the dimensions of the external casing 20, ensuring wearability on the patient “P”.