Lenses 1, 2, and 4 as an optical element having a power are cemented together in an optical axis direction. An optical filter 3 is sandwiched between the lenses 2 and 4. Optical elements neighboring each other are cemented together such that a positioning section which is disposed on a side surface of the optical element disposes an appropriate space in an optical axis direction and optical axes of optical elements align in a direction orthogonal to the optical axis. The cemented optical element arrays are cemented together and cut at a line in a cutting operation. By doing this, it is possible to manufacture a small image pickup lens unit, which can be used in an image pickup device, by mass-production and at a low cost.