The invention provides a lamp optical system for an endoscope and a lighting device, which can reduce light intensity deviation among devices. A glass rod (37) is disposed between a light-guiding body (27) inserted in an electronic endoscope (11) and a light source part (31) in a light source device (14). The glass rod (37) reflects illuminating light incident from a rod incident face (37a) while guiding towards a rod shooting face (37b). The diameter of the glass rod (37) is D, and the diameter of a guiding incident face (27a) of the light-guiding body (27) is d. The semi-range full width of the illuminating light with respect to the light strength of the rod shooting face (37b) is Fw. When the maximum offset of the incident position of the illuminating light at the radial direction of the rod shooting face (37b) is A, D)d is satisfied.
