To efficiently supply a large number of short pipes by cutting-off them when a network of complicated piping is constructed or piping is constructed at a plurality of places.

One pipe having a socket (referred to as A-cut pipe, hereafter) and one or more pipes having no socket (referred to as B-cut pipe, hereafter) are obtained by cutting-off a pipe having a socket at one end thereof and a spigot at the other end. A plurality of A-cut pipes and a plurality of B-cut pipes are produced by carrying out this cutting-off operation for a plurality of pipes. The lengths of the A-cut pipes and the number of the A-cut pipes for every length and the lengths of the B-cut pipes and the number of the B-cut pipes for every length are inputted as information necessary for the piping work. Based on the inputted information, the length of one A-cut pipe to be produced from one pipe is determined, and also the lengths of one or more B-cut pipes are determined from the length left after determining the length of the one A-cut pipe such that the length of the final remainder pipe becomes minimum.