A thermal displacement correction device for a machine tool that corrects thermal displacement of a spindle unit includes a memory that defines the spindle unit as a two-dimensional model in a thermally symmetrical plane or in a plane parallel to the thermally symmetrical plane, divides the two-dimensional model into regions, and stores a linear expansion coefficient, a heating coefficient and a radiation coefficient corresponding to each region, and a thermal conductivity coefficient between the each region and its adjacent region; a temperature estimating unit that estimates a temperature of the each region; a correction estimating unit; and a thermal displacement correction unit that performs correction in driving a feed shaft to a command position.

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.