The present invention relates to a movement detection device for detecting a movement of an object in a space range. The movement detection device includes a light source, a light guiding element, at least two light sensing elements and a processing unit. The light sensing elements have an offset therebetween along a first direction such that the object, when moving in the space range, reflects the light from the light source sequentially to the light sensing elements through the light guiding element. The processing unit identifies the movement of the object along the first direction according to a sequence that the light sensing elements detect the light reflected by the object.