PURPOSE: To constitute an ultrasonic probe with satisfactory quality and productivity by forming an acoustic matching layer, which is formed on the front panel of a piezoelectric piece to generate ultrasonic waves, by vapor deposition.

CONSTITUTION: The plasma spraying of ceramic as a first layer 4a is executed and a CVD method is adopted for the plastic of a second layer 4b. For the thickness of each layer, a relation between an acoustic characteristic caused by a spectrum analyzer, for example, and thickness is grasped in advance and the thickness is hourly set and controlled in the case of vapor deposition. The acoustic layer 4 is divided by inserting a slit from the layer 4 to a backing material 3. Thus, since both the first and second layers 4a and 4b of the acoustic layer 4 are formed by vapor deposition, the film thickness can be controlled to be λ/4 or λ/2 of an oscillation frequency without fail. Since the acoustic layers 4 can be simultaneously formed onto plural piezoelectric diaphragms 2 by using the vapor deposition, the productivity can be improved.