We have developed optical-adjustment-free camera modules for mobile phones. Because of the currentboom in mobile phones with built-in cameras, easy camera assembly to speed unit output is important. Adjustment-free manufacturing helps camera module assembly makers deliver mass products with short turnovertime. In particular, focus-adjustment-free cameras can be made smaller and task time speeded up. We have examined the trade off between resolution and optical focal depth for mobile phones. And we have developed a new structure for camera modules that has an optical system set on the CMOS sensor to minimize the margin of error in assembly.