Problem to be solved: to provide a catheter capable of improving the bending rate.The catheter 10 comprises cylindrical members 1 to 4. The cylindrical member 1 includes a polymer actuator and has a circular cross section perpendicular to the longitudinal direction and has a linear shape. The cylindrical member 2 is connected to one end of the cylindrical member 1 and includes a polymer actuator and has a linear shape. The cylindrical member 4 includes a polymer actuator and has a linear shape and is shorter than the cylindrical member 2.The cylindrical member 3 includes a polymer actuator, one end thereof is connected to the cylindrical member 2, the other end thereof is connected to the cylindrical member 4 and has a curved shape. Each of the cylindrical members 2 and 4 has a cross-sectional secondary moment which is smaller than the secondary moment of the cross section in the case where the cross section is true in the at least one direction.Diagram【課題】屈曲率を向上可能なカテーテルを提供する。【解決手段】カテーテル10は、筒部材1~4を備える。筒部材1は、高分子アクチュエータを含み、長さ方向に垂直な断面形状が真円であり、直線形状を有する。筒部材2は、筒部材1の一方端に連接されるとともに高分子アクチュエータを含み、直線形状を有する。筒部材4は、高分子アクチュエータを含むとともに直線形状を有し、筒部材2よりも短い。筒部材3は、高分子アクチュエータを含み、一方端が筒部材2に接続され、他方端が筒部材4に接続され、湾曲形状を有する。筒部材2,4の各々は、少なくとも1つの方向において、断面形状が真円である場合の断面二次モーメントよりも小さい断面二次モーメントを有する。【選択図】図1
