A three-dimensional direction detecting device, including: an electromagnetic radiation source and a sensing module. The electromagnetic radiation source is used to generate electromagnetic radiations. The sensing module has a plurality of sensing elements for receiving different radiation energies generated by the electromagnetic radiations from different spatial angles. Therefore, the sensing elements respectively receive the different radiation energies from different spatial direction angles generated by the electromagnetic radiation source relative to the sensing elements, so that the value of a spatial direction angle of the electromagnetic radiation source relative to the sensing module is obtained according to the magnitude relationship of the radiation energies received by the sensing module.