A light source apparatus for endoscopic imaging includes a light source for emitting at least narrow band blue light and narrow band green light, to illuminate an object in a body cavity. The light source is changeable over between field sequential lighting and simultaneous lighting. The light source, upon setting of the field sequential lighting, emits the narrow band blue light and narrow band green light in a discrete manner, and upon setting of the simultaneous lighting, simultaneously emits the narrow band blue light and narrow band green light. A connector is connectable with an endoscope having a complementary color image sensor of yellow, magenta and cyan, for imaging the object. A controller sets the field sequential lighting assuming that the endoscope is connected to the light source and assuming that the light source is used for emitting the narrow band blue light and narrow band green light.
