A lead-free solder alloy includes bismuth (Bi), content of which is equal to or greater than 56 wt % and equal to or less than 57.5 wt %, indium (In), content of which is equal to or greater than 0.05 wt % and equal to or less than 1.0 wt %, and the balance of tin (Sn) and another unavoidable impurity. The lead-free solder alloy of the disclosure may enable bonding with improved ductility and thermal shock reliability while not having a large melting point change compared to an Sn-58Bi alloy.