A smart vortex generator including a main body, disposed on a body surface, such as a main wing of aircraft, making a boundary to a flow of fluid, and at least a part of which includes a shape memory alloy. A form of the main body, depending on a temperature increment/decrement of the fluid, changes between (1) a first form capable of suppressing a flow separation by a vortex generation and (2) a second form capable of suppressing a turbulent flow, by a phenomenon that the shape memory alloy undergoes a phase transformation between a high-temperature-side stable phase and a low-temperature-side stable phase. The smart vortex generator demonstrates a multi-directional characteristic depending on a temperature change, such that no energy supply from the outside is required. The structure is simple, and repairs and maintenance as well as installation to existing wings are easy.