To provide a capacity evaluation device of a pile capable of accurately evaluating the capacity of the pile not subjected to a load test.

The capacity evaluation device of the pile is equipped with an estimate N value calculation means 101 for calculating the estimated N value of a pile driving point from a ground investigation results 107 obtained at a plurality of points, a relational expression forming means 102 for forming the relational expression of the estimated N value with execution data 108 obtained during the execution of the pile 1 corresponding thereto, an evaluated N value calculation means 103 for inputting the execution data of the pile to the relational expression to calculate the evaluated N value of the pile driving point, a support force calculation formula forming means 104 for performing the load test with respect to a plurality of piles of which the evaluated N values are calculated to calculate actually measured support force to form a support force calculation formula from a plurality of the evaluated N values and the actually measured support force, a support force calculation means 105 for inputting the evaluated N value of the pile not subjected to the load test to the support force calculation formula to calculate calculated support force and an output part 106 for displaying the capacity evaluation result of the pile based on the calculated support force.