1. A gesture detection device, comprising: a detection surface having a normal direction; a first image sensor disposed on the detection surface and capturing a first image along the normal direction; a second image sensor disposed on the detection surface offsetting a predetermined distance from the first image sensor along a Z-axis and capturing a second image along the normal direction; and a processing unit configured to calculate an X-axis coordinate according to a position of a pointer image in the first image or a pointer image in the second image, calculate a Y-axis coordinate according to a disparity of the pointer images in the first image and the second image, and identify a click event of the Z-axis when a size difference of the pointer images between the first image and the second image is larger than or equal to a difference threshold.