A data acquisition system is realized to image electrical conductivity of biological tissues via contactless measurements. This system uses magnetic excitation to induce currents inside the body and measures the magnetic fields of the induced currents. A magnetically coupled differential coil system is scanned on the conductive object by a computer controlled scanning system. A data acquisition system is constructed using a PC controlled lock-in amplifier. 1.64V secondary voltage difference can be measured for 0.6 S/m solution. The average data acquisition time is 4.67 sec/mm(2). 8 mm diameter objects with conductivity 0.2 S/m can be detected with this system.