A message sequence generation method and a message sequence generation device, by which a message sequence with an error handling added thereto can be efficiently generated. The method includes setting an action for a specific phenomenon in the phenomenon causal relationship model, associating each element included in the message sequence information with each phenomenon to generate element/phenomenon correspondence information, storing the element/phenomenon correspondence information into a memory device, and acquiring the action set for the phenomenon corresponding to each element and the action set for another phenomenon caused by the phenomenon, from the element/phenomenon correspondence information, and adding the actions to the element as an error handling.