At the J-PARC E16 experiment[1], we measure mass spectra of vector mesons in nuclei from the e+e- decay channel with high precision and high statistics. We have developed the trigger system consisting of newly developed ASD ASICs which can extract signals from the GEM foil used as a cathode plane of the induction gap in a GEM chamber and digital electronics using FPGAs which processes binary signals from the ASIC.