PROBLEM TO BE SOLVED: To provide a packaging method and a packaging line of an electronic component which improve preservative quality of flux and a reinforcement resin and ensures reliability of a solder joint part.SOLUTION: In an electronic component packaging method, an electronic component having multiple solder bumps is mounted on a substrate having a mounting region where multiple corresponding lands are provided. The electronic component packaging method includes the steps of: applying a thermosetting resin having first viscosity C1 to a reinforcement position set in a peripheral part of the mounting region so that the thermosetting resin contacts a peripheral part of the electronic component when the electronic component is mounted; applying flux, having second viscosity C2 that satisfies C1≤C2, to the multiple solder bumps; mounting the electronic component on the substrate so that the bumps, to which the flux is applied, are landed on the lands; and heating the substrate, on which the electronic component is mounted, to melt the bumps and hardening and cooling the thermosetting resin to join the electronic component to the substrate.