In this study, we focus on the alteration of negative dielectrophoresis (n-DEP) caused by small amount of DNA labeling on the microbeads and propose a new design of microfluidic device for more sensitive DNA detection. In previous study, we proposed a new electrical technique for rapid detection of DNA amplified by polymerase chain reaction (PCR). The method is based on dramatic alteration of dielectrophoresis (DEP) characteristics of microbeads caused by DNA labeling. The DNA labeling of microbeads alters their DEP behavior in such a way that they are trapped on a microelectrode under the action of positive DEP (p-DEP), whereas bare microbeads are not, due to the n-DEP. However, this method requires at least 105 copies of DNA labelling on a microbead to alter the DEP behavior of microbeads from negative to positive. As a result, we are able to distinguish bare microbeads and microbeads labeled with DNA at DNA to microbead ratio of 3×103: 1 and 3×104: 1, based on the n-DEP alteration.