This paper describes the continuous flow operation of membraneless sodium perborate fuel cell using acid/alkaline bipolar electrolyte. Here, hydrazine is used as a fuel and sodium perborate is used as an oxidant under Alkaline-acid media configuration. Sodium perborate affords hydrogen peroxide in aqueous medium. In our operation, the laminar flow based microfluidic membranleless fuel cell achieved a maximum power density of $27.2mW;cm^{-2}$ when using alkaline hydrazine as the anolyte and acidic perborate as the catholyte at room temperature with a fuel mixture flow rate of $0.3mL;min^{-1}$. The simple planar structured membraneless sodium perborate fuel cell enables high design flexibility and easy integration of the microscale fuel cell into actual microfluidic systems and portable power applications.