1. A numerical controller connectable to a plurality of devices, the numerical controller comprising:a connection information acquisition unit that acquires connection information on the devices, including information indicating a connection order and a kind of each of the devices by communicating with each of the devices;
a connecting data creation unit that creates connecting data using the connection information;
a connection processing execution unit that executes connection processing with each of the devices using the connecting data;
a detailed information acquisition unit that acquires detailed information from each of the devices subjected to the connection processing; and
a connection information comparison unit that compares the connection information with a connection setting parameter,
wherein the connecting data creation unit creates connecting data using the connection information when a comparison result acquired by the connection information comparison unit shows a problem between the connection information and the connection setting parameter.