A method and an apparatus for automatically composing a program for conducting sequential control of operations which are successively performed by various equipment units for a production line. These operations are grouped into operation blocks each having a sequence of unit operations so that each operation block can be conducted independently of the other blocks. Standardized step ladder patterns for the operation steps constituting each operation block is stored before the program composition. First data for describing the operation blocks and the ordinal relationship between the operation blocks is input. Second data for describing specific operations of the operation steps constituting each of the operation blocks and third data designating the order of execution of the operation steps are input and stored. The step ladder pattern corresponding to one of the operation steps constituting each operation block and the second data for this operation step are read out. The second data is appended to the read step ladder pattern to form a step ladder element. These operations of reading and step ladder element formation are repeated with respect to the operation steps in order of upper to lower operation steps based on the third data. This operation is performed with respect to all the operation blocks based on the first data.