A mounting structure is provided that can suppress flux from spreading, secure a connecting strength between a circuit board and an electronic component with underfill, and achieve a stable electrical connection between lands and terminals. The mounting structure is configured with a flat electronic component and a circuit board, and a plurality of lands provided on the undersurface of the electronic component and a plurality of terminals provided on the mounting surface of the circuit board so as to correspond to the plurality of lands are bonded with solder. The circuit board includes a means for holding flux separated from the solder in the proximity of at least one of the plurality of terminals.