An actuator, a projection device, and a projection method are provided. The projection method includes the following. A first optical element is disposed in a first frame body. At least one first driving assembly is disposed between a first base and the first frame body. A second optical element is disposed in a second frame body. At least one second driving assembly is disposed between a second base and the second frame body. The first driving assembly is controlled by a first signal to drive the first frame body, such that the first optical element reciprocally swing relative to the first base based on a first actuating axis and a second actuating axis. The second driving assembly is controlled by a second signal to drive the second frame body, such that the second optical element reciprocally swing relative to the second base based on a third actuating axis.