To provide an NC working piston outline data generating device for collectively inputting related data by relieving burden and time on the individual management of non-circular data and condition data other than it.

Non-circular-shape data, and condition data other than it are described in one data sheet. An NC working data generating program 20 reads the data sheet in a step S4, recognizes indication words, i.e., a "start cell", and an "end cell" which are described in the data sheet, so as to take out matrix data within the range of a cell specified by the contents of the succeeding cells in a step S5, takes out condition data other than non-circular-shape data described in the same data sheet in a step S6, and, then, calculates NC data to be given to an NC apparatus based on the condition data and the non-circular-shape data.