The field-emission characteristics of double-gate metallic tip array devices were studied. The array consist of pyramidal shaped molybdenum field emitters with ~20 nm-apex-sizes fabricated by a mold technique. By a self-aligned gate-process, we have fabricated double-gate devices with up to 40 times 40-tips. The measurement of the emission current transfer characteristics as a function of the electron extraction gate bias and of the collimation gate bias showed that the influence of the collimation gate bias on the apex field is a factor of ~5 smaller than that of the extraction gate bias voltage in our devices.