PURPOSE: To clearly distinguish a normal interactive processing from an exceptional interactive processing for coping with a misoperation, so that a design, a study and an evaluation can be executed, by providing a function for displaying so that an exceptional sequence can be distingushed clearly from a normal sequence.

CONSTITUTION: A sequence storing means 1 stores an operation designation and a response designation for an interactive device in accordance with a sequence being an interactive procedure. A sequence read-out means 2 decides whether a sequence read out by discriminating information is an exceptional sequence or not, and when the exceptional sequence is read out, an exceptional sequence instruction 21 is outputted. A display pattern storage means 4 stores a display pattern for a normal sequence, and a display pattern for an exceptional sequence, usually outputs the display pattern for the normal sequence, and when the exceptional sequence instruction 21 is inputted, the display pattern for the exceptional sequence is outputted. A sequence display means 5 displays a sequence on a display means 3 by using the display pattern inputted from the display pattern storage means 4.