PROBLEM TO BE SOLVED: To provide: a lead-free solder containing solder paste composition capable of suppressing the development of cracking in a solder joint portion and an electronic component electrode separation phenomenon by the solder joint portion even in an environment of receiving a harsh cold shock cycle and a vibration load; a solder joint body structure formed by using the composition; and an electronic circuit board having the solder joint body structure.SOLUTION: A solder paste composition comprises: a lead-free solder alloy and a flux, the lead-free solder alloy containing 2 to 4 mass% of Ag, 1 mass% or less of Cu, and 1.5 to 3 mass% of Bi, a reminder thereof being substantially Sn, the flux containing synthetic resin, a thixotropic agent, an activator, and a solvent, and an adhesive force of a flux residue formed by the flux being not less than 0.2 N/mmafter being subjected to 2000 cycles of a cold shock test with one cycle set as -40 to 125°C/30 minutes.SELECTED DRAWING: Figure 1
