Catheter and method for producing same

A catheter having a distal side and a proximal side comprising:

• a shaft having an outer tubular member, and
• an insertion member wherein at least a part of the insertion member in an axial direction thereof is disposed in the outer tubular member,
• at least one of the outer tubular member or the insertion member is a multilayer tube having a first layer and a second layer laminated with the first layer,
• wherein in a cross-section that is perpendicular to an axial direction of the multilayer tube, a ratio of a cross-sectional area of the second layer to a cross-sectional area of the first layer (cross-sectional area of the second layer/cross-sectional area of the first layer) is 0.7 or less,
• a material constituting the second layer has a higher degree of crystallinity than that of a material constituting the first layer,
• wherein the material constituting the second layer has a lower melting point than that of the material constituting the first layer, and
• wherein in the cross-section that is perpendicular to the axial direction of the multilayer tube, an initial roundness calculated by equation (1) is 92% or more,
• wherein equation (1) is:
• initial roundness (%)=(a minor axis outer diameter of the multilayer tube/a major axis outer diameter of the multilayer tube)×100, and (1)
• wherein the outer tubular member and the insertion member are relatively movable in a distal and proximal direction.