The prevent invention provides an image display device with pupil tracking function and pupil tracking device thereof, which includes a light-source module, a micro mirror module, a optical module, a sensor and a controller. The controller is electrically connected to the micro mirror module and the sensor the light-source module, the micro mirror module, the optical module and the sensor are configured along a predetermined optical path. A point-light provided by the light-source module is reflected by the micro mirror module to form a surface light source, and the surface light source is reflected by the optical module to form a detecting light towards an eye surface. The eye surface has a pupil surface and a non-pupil surface surrounding the pupil surface. The detecting light is reflected by the pupil surface to form a reflected light towards the sensor, and the sensor transmits a pupil position signal to the controller according to the reflected light.本發明公開一種具有瞳孔追蹤功能的影像投影裝置及其瞳孔位置追蹤裝置。瞳孔位置追蹤裝置包括一光源模組、一微鏡模組、一光學模組、一感測模組以及一控制模組。控制模組電性連接於微鏡模組與感測模組,且光源模組、微鏡模組、光學模組以及感測模組沿著一預定光學路徑佈置。光源模組所提供的一點光源通過微鏡模組的反射以形成一面光源。面光源通過光學模組的反射以形成投向眼球表面的一偵測光源,且眼球表面具有瞳孔表面以及圍繞瞳孔表面的非瞳孔表面。藉此,偵測光源能通過瞳孔表面的反射以形成投向感測模組的一反射光源,且感測模組能依據反射光源以傳送瞳孔位置訊號至控制模組。D‧‧‧影像投影裝置1‧‧‧光源模組2‧‧‧微鏡模組3‧‧‧光學模組4‧‧‧眼球表面41‧‧‧瞳孔表面42‧‧‧非瞳孔表面5‧‧‧感測模組6‧‧‧控制模組L1‧‧‧第一點光源L11‧‧‧第一面光源L12‧‧‧偵測光源R1‧‧‧第一反射光源R2‧‧‧第二反射光源