To provide a time-series data analysis device which allows to compare time-series data easily.A time-series data analysis device analyzes the time-series data output by a machine tool, the time-series data analysis device including a time-series data acquisition unit configured to acquire the plurality of time-series data including operation conditions and operation results of the machine tool, a classification unit configured to classify the plurality of time-series data according to their respective operation conditions, a display control unit configured to perform control for displaying the plurality of time-series data according to the respective operation condition into which data was classified in the form of a list, and a calculation unit configured to calculate differences in the operation results for a plurality of time-series data selected from the plurality of time-series data included in one operation condition into which data was classified, wherein the display control unit performs control for displaying the calculated differences.