The Gamma-Ray Astro-Imager with Nuclear Emulsion (GRAINE) project is aimed at the precise observation of astronomical gamma-ray sources in the energy range of 10 MeV-100 GeV using a balloon-borne telescope utilizing a nuclear emulsion, which can help realize precise imaging with a high angular resolution (1.0◦ at 100 MeV), polarization sensitivity and a large aperture area (10 m^2). The third balloon-borne experiment is GRAINE2018, performed in Australia with an aperture area of 0.4 m^2, in which the brightest known gamma-ray source, the Vela pulsar, was clearly detected and the emulsion gamma-ray telescope with the highest angular resolution in this energy region was established. Although a high-speed scanning system, which was used for scanning all tracks recorded in emulsion films in GRAINE2018, was not accurate enough to ensure the optimum performance of the emulsion film. We developed new high-precision scanning system for only the gamma-ray events detected by the high-speed scanning system. We will report a performance demonstration of the new scanning system for GRAINE2018, and will report the next experiment, GRAINE2023, with an aperture area of 2.5 m^2.