The present invention provides a composite lens system, a lens unit and an image pickup device, wherein the productivity is enhanced, while maintaining an optical performance, by achieving an axis-aligning adjustment for the composite lens system easily and appropriately. The positioning of adjacent lenses in a direction of optical axes is achieved by bringing optically non-functioning faces of the adjacent lenses into engagement with each other directly or indirectly with another member interposed therebetween. The lenses have adjusting faces which are formed thereon, so that angles formed by the lenses with respect to the optical axes are different from each other, and which are used for an axis-aligning adjustment for the lenses. The axis-aligning adjustment is achieved by an adjusting member disposed to engage both the adjusting faces of the adjacent lenses.