We have demonstrated the enhancement of laser-to-core energy coupling with magnetized fast isochoric laser heating on the GEKKO-LFEX laser facility. The maximum coupling of 8% was achieved by application of external magnetic field, which was degraded gradually by increasing the heating laser energy with keeping both pulse duration and spot diameter unchanged. The obtained energy couplings are consistent with simple calculation models. The model predicts that 20-35% of energy coupling is