Provided is an improved medical elongated body which can be inserted into a biological lumen and can be restrained from unintentionally moving at a target site inside the biological lumen. The medical elongated body includes a main body portion that extends in an axial direction, and a projection portion that protrudes radially outward on an outer circumference of the main body portion and extends in the axial direction. One surface of the projection portion in a circumferential direction has higher sliding properties than an other surface of the projection portion in the circumferential direction.
