To provide an electronic circuit for driving the electronic circuit where an ECL circuit and a TTL circuit coexist by one power source of a negative voltage or a positive voltage and a ground potential.

This electronic circuit is constituted of the ECL circuit 1 of a negative power source system, the TTL circuit 2 for being shifted to a negative potential side by shifting the driving voltage VCC of the TTL circuit 2 of a positive power source system to the ground potential and the driving voltage VEE to a negative potential and being driven by the same power source as the ECL circuit 1, an ECL/TTL conversion circuit 4 for converting output signals from the ECL circuit 1 to the signals of the potential suitable for the input signal level of the TTL circuit 2 shifted to the negative potential side and driven and transmitting them to the TTL circuit 2 and a TTL/ECL conversion circuit 4 for converting the output signals from the TTL circuit 2 shifted to the negative potential side and driven to the signals of the potential suitable for the input signal level of the ECL circuit 1 and transmitting them to the ECL circuit 1.