The purpose of the invention is the simplification of a task of changing a control program upon a control device which is in use. A support device comprises: a computing part computing, for each unit program which configures a control program, identification information according to the content of each of the unit programs; a first transferring part transferring the unit programs and the identification information which is associated with the unit programs to a control device; a generating part generating changed unit programs according to a change operation upon any of the unit programs which configure the control program; and a second transferring part transferring the changed unit programs to a control device which is in use on condition that identification information is present on the control device which is identical to the identification information which is associated with the unit programs which configure the control program.