A waveform display device includes a position information acquisition unit for acquiring position information of a drive shaft of a machine tool in a time series manner, a time designation unit for designating a time section that is a display target in a time series of the position information, a tangent direction speed calculation unit for calculating a tangent direction speed of a tool tip end point of the machine tool based on the position information and configuration information of the machine tool, a distance calculation unit for converting the time section into a distance between two points on a machined surface of the machine tool based on the tangent direction speed, and a display unit for displaying the distance between the two points.

A tool status display device includes a memory, a processor, and a display. The memory is configured to store first data that associates each attachment surfaces with each tools, and second data that identifies whether tool nose positions of noses of the tools have been measured. The processor is configured to determine whether designated tool among the plurality of tools is attached to designated attachment surface among the plurality of attachment surfaces based on the first data and third data that associates the designated tool with the designated attachment surface. The processor is configured to determine whether designated tool nose positions of the designated tool among the tool nose positions have been measured based on the third data and the second data. The display is configured to show whether the designated tool is attached to the designated attachment surface and whether the designated tool nose positions have been measured.