The invention relates to a sound wave transmitting device for depth measuring instrument, which belongs to the technical field of sonar measurement equipment for underwater survey using sound wave, and particularly relates to a high-power sound wave transmitting device for depth measuring instrument. The device mainly comprises a transmission pulse frequency dividing frequency, a transmission loop drive module, a transmission wave power main loop module, a protection module and an energy converter, wherein the transmission pulse frequency dividing module receives a transmission pulse signal from a depth measuring instrument control circuit, and transmits transmission pulse signals of positive and negative half cycles of transmission wave formed respectively after frequency division to left and right transmission loop drive modules; the left and right transmission loop drive modules drive each switch tube of full bridge circuit of the transmission wave power main loop module; the transmission wave power main loop module loads high voltage direct current to the energy converter through the full bridge circuit formed by four switch tubes to form transmission sound wave of the depth measuring instrument; and the protection module acquires a signal from the power main loop module, and a control signal is output when the circuit has exceptional situation such as short circuit and the like to stop all the transmissions so as to protect transmission circuits. Quality of sound wave transmission of the depth measuring instrument can be greatly improved by such high-power transmission circuit without transformer, and the device has wide application prospect.