An ultrasonic probe having a first ultrasonic transmitter-receiver head having a plurality of first ultrasonic transducers carrying transmission and reception of ultrasounds, the plurality of first ultrasonic transducers being arranged in a predetermined first direction. The ultrasonic probe also has a second ultrasonic transmitter-receiver head, detachably loaded onto the first ultrasonic transmitter-receiver head, having a plurality of second ultrasonic transducers carrying transmission and reception of ultrasounds, the plurality of second ultrasonic transducers being arranged in a second direction intersecting the first direction when loaded. The second ultrasonic transmitter-receiver head monitors a state that a puncture needle to be punctured inside a subject is inserted into the inside of the subject. According to the present invention it is possible to implement an ultrasonic probe suitable for both use of a normal diagnosis and a puncture and is capable of contributing to a reduction of the cost. An ultrasonic diagnostic apparatus having such an ultrasonic probe is also described.