Abstract: According to one embodiment, a grain size estimation device includes an acquisition unit that acquires a captured image of a surface segment of an object inducing metal; and an estimation unit that estimates a grain size of the surface segment of the object indicated in the acquired image, based on a predictive model generated by machine learning using images of metal surfaces and grain sizes in the metal surfaces as training data.

Abstract: A manufacturing line includes a receiving unit that receives sensor data indicative of a measured value by a sensor provided near a manufacturing device constituting a manufacturing line, a sensor determining unit that determines whether the measured value indicated by the sensor data exceeds a first sensor threshold value indicative of a predetermined range, and a notifying unit that sends a sensor abnormality notification, which notifies a user of the client terminal that the manufacturing device malfunctions, in a case where the sensor determining unit determines that the measured value exceeds the first sensor threshold value.