To provide a puncture needle device for an ultrasonic endoscope in which, when a double-thread male screw arranged in a mouth ring side of the ultrasonic endoscope and a double-thread female screw arranged in the puncture needle device side are tightened, a relative rotational direction position to the mouth ring of the puncture needle device comes to the predetermined position without fail.
Equipped with a first female screw 32A and a second female screw 32B, in which both of root diameters in an edge part in an inlet side formed with circumferential phases mutually shifted by 180 degrees on an inner circumferential surface of a connection opening of a cylindrical connection part 31, are larger than the outer diameter of a first male screw 18A and the outer diameter of a second male screw 18B. For the first female screw 32A, the root diameter is constant up to a first end position advanced just by integer pitch with the edge part in the inlet side as a reference, for the second female screw, the root diameter, from the first end position advanced just by the integer pitch with the edge part in the inlet side as the reference to the second end position 32B4 one-pitch short of this first end position, is larger than the outer diameter of the second male screw and smaller than the outer diameter of the first male screw, moreover, the root diameter from the edge part in the inlet side to right before the second end position is constant.
SATO MASAYASU
Daisuke Ando
Kuniyo Miura