A dielectrophoretic particle concentrator includes first substrate, detection electrodes, second substrate, protrudent structure and edge wall structures. The first substrate extends along first direction. The detection electrodes are disposed on the first substrate and extend along second direction. The second direction crosses the first direction. The second substrate is disposed over the first substrate and extends along the first direction. The protrudent structure is disposed on the second substrate and protruded towards the first substrate. A top portion of the protrudent structure includes a line-like structure extending along the second direction and adjacent to the detection electrodes. The edge wall structures are integrated with the first substrate and the second substrate, to form pipe-like structure to enable a fluid flowing through the protrudent structure from an end to another end. The particle concentration can trap particles at the gap by continuously trap mode or bidirectional trap mode with changing frequency.