A flash memory includes a substrate with a protrusion, a control gate, two floating gates, and a dielectric layer. The protrusion extends from a top face of the substrate. The control gate is formed on the protrusion of the substrate and extendedly covers opposite sidewalls of the protrusion. The floating gates are respectively formed on top of the protrusion and being on two opposite sides of the control gate. The dielectric layer is sandwiched the control gate and each of the two floating gates. Because of the arcuate control gate used in the flash memory, the controllability of the control gate is increased and the memory cell window is enhanced.