A surface position detecting apparatus comprises a light-sending optical system which makes first light from a first pattern and second light from a second pattern incident at different incidence angles to a predetermined surface to project an intermediate image of the first pattern and an intermediate image of the second pattern onto the predetermined surface; a light-receiving optical system which guides the first light and the second light reflected on the predetermined surface, to a first observation surface and to a second observation surface, respectively, to form an observation image of the first pattern on the first observation surface and an observation image of the second pattern on the second observation surface; and a detecting section which detects position information of the observation image of the first pattern on the first observation surface and position information of the observation image of the second pattern on the second observation surface and which calculates a surface position of the predetermined surface, based on the position information of the observation image of the first pattern and the position information of the observation image of the second pattern.