An observation apparatus which observers operations of an observation target apparatus, and which includes: an output signal acquisition unit for sequentially acquiring signal values by observing signals outputted by the observation target apparatus; a state storage unit for sequentially storing the acquired signal values; a determination unit for determining whether a first signal value newly acquired is identical with a second signal value which is acquired prior to the first signal value, and which is stored in the state storage unit; and a separation unit for separating and outputting a signal sequence, which includes a plurality of signal values acquired between the first signal value and the second signal value, as transactions of the output signals, on condition that it is determined that the first signal value is identical with the second signal value.