A life predicting method for a solder joint includes a step of referring to a temperature history of a measurement object having a solder joint, a step of examining at least one physical quantity selected from the group consisting of amplitude, a cycle number, a mean temperature, and a periodic length of a temperature variation with a cycle count method from the temperature history, a step of calculating a strain range by utilizing a previously prepared response surface from the physical quantity examined with the cycle count method, and a step of calculating a strain range increasing rate from a strain range with reference to a previously obtained damage index and a strain variation history of the strain range.