The manipulation and detection of rare cells are important for many applications in early disease diagnosis and medicine. This study presents a dielectrophoresis (DEP) microfluidic enrichment platform combined with a built-in capacitive sensor for circulating tumor cell detection. The microchip is composed of a lollipop-shaped gold microelectrode structure under a polydimethylsiloxane chamber. A prototype of the device was fabricated using standard micromachining technology. With the proposed device, target cells (in this study, A549 non-small human lung carcinoma and S-180 sarcoma cell lines) are firstly guided toward the center of the working chamber via DEP forces. Then, the target cells are captured by an electrode immobilized by anti-EGFR, which has high affinity toward the target cells. After the cell concentration process, the differential capacitance is read to detect the presence of the target cells. Numerical simulations and measurement experiments were performed to demonstrate the high sensitivity of differential capacitive sensing. The obtained results show high sensitivity for S-180 cell detection (3 mV/cell). The proposed platform is suitable for rapid cancer diagnoses and other metabolic disease applications.