(57) An ultrasonic probe for an ultrasonic medical diagnostic apparatus which is composed of a plurality of piezoelectric vibrators (1) with electrodes (8, 9) attached onto both surfaces thereof and one or two acoustic matching layers (3, 6) which are provided on the surface of one electrode (8) of the piezoelectric vibrator. One of the acoustic matching layers is made of thermosetting resin such as epoxy resin mixed with carbonyl group material. A backing load member (2) which is made of epoxy resin or rubber material mixed with microspheres and metal or insulator powder is provided on the surface of the other electrode (9) of the piezoelectric vibrator. A filler material (5) which is made of rubber material or thermosetting resin is filled between each of said piezoelectric vibrators.