A jet-breaker device for a jet irrigation apparatus having a supporting frame with a portion for anchoring it to the launch pipe of an irrigation apparatus, jet-breaker means connected to the frame and designed to at least partially project out of the nozzle of the apparatus for interfering with the outlet jet. The jet-breaker means include at least one jet-breaking element which is designed to oscillate with a predetermined frequency in a plane between a position substantially aligned with the nozzle for interfering with the jet and causing partial breaking thereof, and a position misaligned with the nozzle in which it does not interfere with the jet. The jet-breaker means are motorized for controllably adjusting the oscillation of the jet-breaking element and changing the oscillation frequency thereof. A jet irrigation apparatus incorporating the jet-breaker device.