A damage estimation device that estimates damage in a predetermined portion associated with an operation of a work machine, the damage estimation device comprising: an operation parameter acquisition unit that acquires an operation parameter related to the operation of the work machine; a damage estimation model storage unit that stores a damage estimation model constructed by machine learning using training data with the operation parameter as an input value and a damage parameter related to damage in the predetermined portion of the work machine as an output value; and an estimation unit that estimates the damage parameter by inputting the operation parameter acquired by the operation parameter acquisition unit to the damage estimation model stored in the damage estimation model storage unit, characterized in that the damage estimation model includes a plurality of damage estimation models different for each specification of the work machine, the damage estimation model storage unit stores each of a plurality of specification parameters related to a specification of the work machine and each of the plurality of damage estimation models in association with each other, the damage estimation device further includes a specification parameter acquisition unit that acquires a specification parameter of a work machine to be estimated, and a selection unit that selects a damage estimation model associated with the specification parameter acquired by the specification parameter acquisition unit from among the plurality of damage estimation models, and the estimation unit estimates the damage parameter by inputting the operation parameter acquired by the operation parameter acquisition unit into the damage estimation model selected by the selection unit. an operation parameter acquisition unit that acquires an operation parameter related to the operation of the work machine; a damage estimation model storage unit that stores a damage estimation model constructed by machine learning using training data with the operation parameter as an input value and a damage parameter related to damage in the predetermined portion of the work machine as an output value; and an estimation unit that estimates the damage parameter by inputting the operation parameter acquired by the operation parameter acquisition unit to the damage estimation model stored in the damage estimation model storage unit, characterized in that the damage estimation model includes a plurality of damage estimation models different for each specification of the work machine, the damage estimation model storage unit stores each of a plurality of specification parameters related to a specification of the work machine and each of the plurality of damage estimation models in association with each other, the damage estimation device further includes a specification parameter acquisition unit that acquires a specification parameter of a work machine to be estimated, and a selection unit that selects a damage estimation model associated with the specification parameter acquired by the specification parameter acquisition unit from among the plurality of damage estimation models, and the estimation unit estimates the damage parameter by inputting the operation parameter acquired by the operation parameter acquisition unit into the damage estimation model selected by the selection unit.