A tube main body (2) having a distal end portion (8) and a proximal end portion (11) connected via a curved portion (10), a cuff (3) attached on the outer circumferential surface of the tube main body (2) , A suction lumen (12) extending along the center axis (O1) of the inner peripheral surface of the tube body (2) is located closer to the base end portion (11) side than the cuff (3) (12b) penetrating from the inner wall opening (26) formed in the inner wall of the suction lumen (12) to the outer wall opening (27) formed in the outer peripheral surface at the position of the suction lumen (12) Wherein the suction port (12b) is formed such that one point on a straight line connecting the two third vertex portions (73) where the first incision portion (61) and the second incision portion (62) intersect is taken as a viewpoint, and the center axis line ), A top section where the first notch (61) and the outer circumference face meet, and A cross section orthogonal to the center axis line (O1) than a first angle formed by a straight line connecting the first cut portion (62) and the three apex portions (73), a top portion where the second cut portion (62) And the third apex (73) is formed smaller than the second angle formed by the straight line connecting the third apex (73) and the third apex (73).湾曲部(10)を介して先端部(8)と基端部(11)とが繋がっているチューブ本体(2)と、前記チューブ本体(2)の外周面上に取り付けられたカフ(3)と、を備え、前記チューブ本体(2)の内周面の中心軸線(O1)に沿って延在する吸引用ルーメン(12)は、前記カフ(3)よりも前記基端部(11)側の位置で、前記吸引用ルーメン(12)の内壁に形成された内壁開口(26)から前記外周面に形成された外壁開口(27)まで貫通する吸引口(12b)を通じて外方と連通し、前記吸引口(12b)は、第1切込部(61)と第2切込部(62)が交わる2つの第3頂部(73)を結ぶ直線上の一点を視点として、前記中心軸線(O1)と直交する断面と、前記第1切込部(61)及び前記外周面が交わる頂部と前記第3頂部(73)とを結ぶ直線と、がなす第1の角度よりも、前記中心軸線(O1)と直交する断面と、前記第2切込部(62)及び前記外周面が交わる頂部と前記第3頂部(73)とを結ぶ直線と、がなす第2の角度が小さく形成されている。
