A quality estimation device includes: a first acquisition unit configured to acquire first information pertaining to the positioning of a worker executing a work step included in a process for manufacturing a product on a production line; a second acquisition unit configured to acquire second information pertaining to the usage condition of a tool the worker uses in the work step; an estimation unit configured to estimate the quality of a product being made through the work step according to the degree to which the positioning of the worker and the degree to which the usage condition of the tool represented by the acquired first information and the acquired second information conforms to a predetermined first standard and a predetermined second standard; and an output unit configured to output information pertaining to the result of estimating the quality of the product.