FAILURE PROBABILITY EVALUATION DEVICE AND FAILURE PROBABILITY EVALUATION METHOD

Provided are: a technique for improving failure probability evaluation precision, even when the center and tails of an occurrence frequency distribution for stress or strength, or a physical quantity associated with stress or strength, such as load, for example, do not conform to the same probability distribution, by precisely estimating a tail probability density function; and a high-precision failure probability evaluation device. This results in a failure probability evaluation device comprising: a probability density estimation function estimation unit comprising a storage unit for storing a failure model, which computes the probability of failure in a mechanical system, and a probability variable occurrence frequency distribution used in the failure model, a tail estimation unit for estimating a probability density function for the tails of the occurrence frequency distribution on the basis of an extreme-value statistical model, a center estimation unit for estimating a probability density function for the parts of the occurrence frequency distribution other than the tails, and a connection unit for using the probability density function for the tails and the probability density function for the parts other than the tails to estimate an overall probability density function for the occurrence frequency distribution; and a failure probability computation unit for computing the probability of failure in the mechanical system on the basis of the overall probability density function and the failure model.