In an ultrasonic probe including an element part 1 for transmitting and receiving ultrasonic waves, a relay cable 2 connected to the element part 1 and an oscillation mechanism part for oscillating the element part, a cross section of the relay cable 2, which is taken perpendicularly to a rotation axis 3 of the oscillation that is provided to the element part 1 by the oscillation mechanism part, has at least two arc-shaped parts smoothly connected each other, more specifically, S-shape arc-shaped parts or reversed S-shaped parts. In addition, the relay cable 2 is drawn from the surface of the element part 1 facing the rotation axis 3. In this manner, the stress applied to the relay cable 2 during the oscillation of the element part 1 can be dispersed, thereby improving durability of the relay cable 2.