Disclosed is an electronic component mounting line on which a substrate undergoes solder paste printing, electronic component placements, and then reflow, while being moved from upstream to downstream. The line includes: a substrate feeding machine; a printing machine for applying solder paste to a first placement area of the substrate; a first electronic component placement machine for placing a first electronic component on the first placement area; a second electronic component placement machine for dispensing a thermosetting resin onto a reinforcement position on a peripheral edge portion of a second placement area of the substrate, and for placing on the area the second electronic component having solder bumps; and a reflow machine for bonding the electronic components to the substrate, by heating and cooling the resultant. The second electronic component is placed after the resin is dispensed, such that a peripheral edge portion thereof comes in contact with the resin.