A lifetime estimation device to estimate a lifetime of a rolling bearing assembly comprising inner and outer rings includes a buildup height estimation unit to estimate in accordance with a predetermined rule a buildup height of the indentation based on the inputted depth of the indentation or the inputted indentation size; and a lifetime estimation unit to estimate the lifetime of the rolling bearing assembly, the lifetime estimation unit being configured to determine a preliminary estimate of the lifetime of the rolling bearing assembly based on a dynamic equivalent load, determine a rate of reduction in a rolling fatigue life based on the buildup height of the indentation, and apply the determined rate of reduction in a rolling fatigue life to the preliminary estimate of the lifetime of the rolling bearing assembly to determine an estimate of the lifetime of the rolling bearing assembly.