A liquid ejection head or microstructure manufacturing method includes providing a substrate with an organic resin material layer for forming a flow passage wall member, and forming a flow path and ejection outlet by partly removing the organic resin material layer by illumination with a laser beam having a pulse width between 2 and 20 picosecs and having a focal point inside the organic resin material layer, with movement of the focal point of the laser beam. The ejection outlet is formed by exposure of the organic resin material to the laser beam condensed by a first lens having a numerical aperture of not less than 0.3, and the liquid flow path is formed by exposure of the organic resin material to the laser beam condensed by a second lens having a numerical aperture which is larger than that of the first lens and which is not less than 0.5.