Micromixer is an important bioMEMS device for mixing samples. In this study, we developed a novel active micromixer using SU-8 to form the microstructure and piezoceramic buzzer to produce the agitation. This device consists of a mixing chamber, inlets and an outlet. It is tolerant of gas bubbles so that the priming process can be achieved. Under the agitation of piezoceramic buzzer, the samples can be well mixed. The advantages of this proposed micromixer include: (1) simple fabrication process; (2) low cost; (3) disposable; and (4) mass-production available.