Provided is a work machine maintenance management system capable of predicting replacement timing of a component of a work machine early. The work machine maintenance management system of this disclosure includes a maintenance management DB server 110 that accumulates maintenance management information of a plurality of work machines and a maintenance management control device 120 that predicts replacement timing of each component of each of the work machines based on the maintenance management information. The maintenance management information includes an actual durable period from start of use to replacement each component of each work machine. The maintenance management control device 120 includes a replacement-factor determining section 121, a service life model creator 122, a failure model creator 123, and a replacement time predictor 126. The replacement-factor determining section 121 determines whether a replacement factor of each component is a service life factor or a failure factor based on an actual durable period of each component of the plurality of work machines. The service life model creator 122 creates a service life model of the component whose replacement factor is determined to be the service life factor by the replacement-factor determining section 121. The failure model creator 123 creates a failure model of the component whose replacement factor is determined to be the failure factor by the replacement-factor determining section 121. The replacement time predictor 126 predicts the replacement timing of each component of each work machine based on the service life model and the failure model.