Event direction detection method that distinguishes an external event from an internal event and detects a direction of an event, includes the steps of: acting as intermediary of input/output of the external event and transferring external event input to an external event output; acting as intermediary of input/output of the internal event and transferring internal event input to an internal event output; transferring the outputs to finite state machine of a block; receiving and editing external event input terminal, via which the external event is input, and external event output terminal via which the external event is output; receiving and editing the first acting and transferring step; receiving and editing internal event input terminal, via which the internal event is input, and internal event output terminal via which the internal event is output; and receiving and editing the second acting and transferring step.