A mechanism to be sequentially controlled is divided into a plurality of functional blocks. Each functional block is assigned to a control block for sequentially controlling the functional block. The mechanism is sequentially and dispersedly controlled by a plurality of control blocks. Synchronization between control blocks is realized by referring to an input/output signal or an internal signal belonging to each control block. Each control block is set with an activation condition for turning on or off its own function so that the whole mechanism can be integrally controlled with an arbitrary condition. The sequence program for each control block is made by using an optimum one from among a conditional type definition, a sequential type definition and a combination of both definitions, in accordance with the control type of the program.