The detection of rare cells, such as circulating tumor cells, circulating fetal cells, and stem cells, is important for medical diagnostics and characterization. The present study develops a handheld electric module which provides stepping electric fields for dielectrophoresis (DEP) to selectively concentrate cervical carcinoma cells (HeLa) from red blood cells, making it low-cost and automated. To observe the experiments, transparent electrodes were fabricated by patterning indium-tin-oxide-coated glass. Positive dielectrophoretic cells were guided toward the center of the microchamber due to the movement of the high-electric-field region. The magnitude of the DEP force acting on HeLa cells is about seven-fold that acting on red blood cells under a given electric field distribution, making it possible to separate HeLa cells from normal blood cells. HeLa cells were successfully concentrated in 160 seconds with an applied peak-to-peak voltage of 16 V at a frequency of 1 MHz.