To improve the accuracy of estimating when a fracture occurred in the metal material. In the estimation apparatus, the fracture temperature estimation unit performs estimate calculation of the fracture temperature of a fractured metal material from the hydrogen embrittlement rate of the fractured metal material, the fracture occurrence time narrowing unit performs calculation by using the temperature information of the installation environment in which the fractured metal material is installed and narrow down the period during which the fracture temperature is obtained as the fracture occurrence period of the metal material, and the fracture time estimation unit performs estimate calculation of the timing of when stress was applied to the fractured metal material during the fracture occurrence period as the timing of when a fracture occurred in the metal material.