We developed a compact high-precision slot-die coating machine for thin-film deposition on a flexible substrate. For smooth and precise coating, air-bearing and linear motor system were employed to minimize velocity ripple. The gap control mechanism is specially designed to have repeatability of gap between nozzle and substrate under 1 ${mu}m$. Due to extremely precise gap control, the machine can coat thin-films down to 50 nm with $200mm{ imes}100mm$ size. A thin film of Ag nano-particle ink is coated for demonstration.