Traditionally, micromixing has been thought to be governed by molecular diffusion. However, the authors consider that advection is important in the mixing enhancement and applicable to micromixing devices in many industrial fields. Here, the Marangoni convection, a type of shear flow induced at gas–liquid free interfaces, is introduced as an additional source for micromixing. To evaluate the proposal, two liquids with different surface tensions values were mixed in a capillary channel fabricated by the photolithography technique. The utility of Marangoni convection was confirmed in rapid mixing by the flow experiments.