An ultrasonic imaging apparatus comprising a probe having an ultrasonic wave transmitting-receiving surface and a probe adaptor (3, 3B, 3C, 3D), the probe adaptor comprising: a contact surface for contact with an object to be imaged; and a fixing portion configured to fix the probe at a given angle and to expose the ultrasonic wave transmitting-receiving surface of the probe to the contact surface side while the contact surface is in contact with the object to be imaged; wherein a contact area between the contact surface of the probe adaptor (3, 3B, 3C, 3D) and the surface of the object to be imaged is larger than a contact area between the ultrasonic wave transmitting-receiving surface of the probe and the surface of the object to be imaged, characterised in that: the object to be imaged is a thigh, an upper arm or an abdomen of a human body; the contact surface has a shape extending along an outer circumference of a cross section of the object to be imaged; the probe is configured so that an operator can grip and move it; and the probe and the probe adaptor (3, 3B, 3C, 3D) are arranged to be moved along an outer circumference of the cross section of the object to be imaged, while exposing the ultrasonic wave transmitting-receiving surface of the probe to the contact surface side and keeping the angle of the probe substantially perpendicular to the outer circumference of the cross section. a contact surface for contact with an object to be imaged; and a fixing portion configured to fix the probe at a given angle and to expose the ultrasonic wave transmitting-receiving surface of the probe to the contact surface side while the contact surface is in contact with the object to be imaged; wherein a contact area between the contact surface of the probe adaptor (3, 3B, 3C, 3D) and the surface of the object to be imaged is larger than a contact area between the ultrasonic wave transmitting-receiving surface of the probe and the surface of the object to be imaged, characterised in that: the object to be imaged is a thigh, an upper arm or an abdomen of a human body; the contact surface has a shape extending along an outer circumference of a cross section of the object to be imaged; the probe is configured so that an operator can grip and move it; and the probe and the probe adaptor (3, 3B, 3C, 3D) are arranged to be moved along an outer circumference of the cross section of the object to be imaged, while exposing the ultrasonic wave transmitting-receiving surface of the probe to the contact surface side and keeping the angle of the probe substantially perpendicular to the outer circumference of the cross section. the object to be imaged is a thigh, an upper arm or an abdomen of a human body; the contact surface has a shape extending along an outer circumference of a cross section of the object to be imaged; the probe is configured so that an operator can grip and move it; and the probe and the probe adaptor (3, 3B, 3C, 3D) are arranged to be moved along an outer circumference of the cross section of the object to be imaged, while exposing the ultrasonic wave transmitting-receiving surface of the probe to the contact surface side and keeping the angle of the probe substantially perpendicular to the outer circumference of the cross section.