A medical acoustic coupler is to be detachably attached to an ultrasonic probe including a graspable trunk portion and a protruding portion protruding in a width direction from the trunk portion, the medical acoustic coupler including a sheet-like elastic member, the elastic member including: a contact portion located at a central portion of the elastic member in a planar view, the contact portion being brought into contact with an ultrasound transmission/reception surface located at a top edge of the protruding portion when the elastic member is attached to the ultrasonic probe； and loop portions located on the opposite sides of the contact portion from each other, the loop portions each forming a loop, wherein, when the elastic member is attached to the ultrasonic probe, the loop portions are hooked around the protruding portion, to fix the elastic member to the ultrasonic probe.
