According to one embodiment, a medical acoustic coupler detachably is provided on an ultrasonic wave radiation surface of an ultrasonic probe. The medical acoustic coupler includes an elastic body. The elastic body has an adhesive force. The elastic body adheres to the ultrasonic wave radiation surface with the adhesive force. The elastic body includes a middle portion, end portions, and groove portions. The middle portion has a size corresponding to the ultrasonic wave radiation surface. The end portions adheres to two opposite side surfaces of the ultrasonic probe. The groove portions are provided between each of the end portions and the middle portion. The groove portions are thinner than the middle portion and the end portions.
