PROBLEM TO BE SOLVED: To provide a sonar device which does not cause panic on a marine organism.SOLUTION: A sonar device which generates a sound wave based on a base signal so as to emit it includes: a base signal generation unit for generating the base signal an amplification unit for amplifying the base signal and a sound wave emission unit which generates the sound wave on the basis of a transmission signal from the amplification unit and which emits a warning sound wave having a low sound pressure and an exploring sound wave having a sound pressure higher than the warning sound wave at that time.
