A guide wire (10, 11, 20), comprising: a core shaft (100, 101) that includes a distal end portion (P1, P11, P2) stepwisely reducing in diameter toward a distal end direction; a coil body that is wound to cover at least a part of an outer periphery of the diameter-reduced distal end portion (P1, P11, P2); and a distal end fixing portion (401, 402) that fixes the distal end of the core shaft (100, 101), and a distal end of the coil body to each other, wherein the distal end portion of the core shaft includes: a small diameter portion (110, 111) that is continuous with the distal end fixing portion (401, 402), a large diameter portion that is positioned in a proximal end direction than the small diameter portion (110, 111) and has a larger outer diameter than a diameter of the small diameter portion (110, 111), and a tapered portion (130, 131) that is continuous with the small diameter portion (110, 111) and the large diameter portion and gradually increases in diameter from the small diameter portion (110, 111) toward the large diameter portion, the core shaft (100, 101) and the coil body being fixed at a portion of the core shaft excluding the tapered portion, characterized in that bending rigidity FR1 of the large diameter portion, bending rigidity FR2 of the small diameter portion (110, 111), and a length L of the tapered portion (130, 131) in an axial direction of the core shaft (100, 101) satisfy the following expressions and: FR 1 / FR 2 / L ≥ 10 1 ≤ L ≤ 3, wherein in the above expressions and, the unit of L is mm. a coil body that is wound to cover at least a part of an outer periphery of the diameter-reduced distal end portion (P1, P11, P2); and a distal end fixing portion (401, 402) that fixes the distal end of the core shaft (100, 101), and a distal end of the coil body to each other, wherein the distal end portion of the core shaft includes: a small diameter portion (110, 111) that is continuous with the distal end fixing portion (401, 402), a large diameter portion that is positioned in a proximal end direction than the small diameter portion (110, 111) and has a larger outer diameter than a diameter of the small diameter portion (110, 111), and a tapered portion (130, 131) that is continuous with the small diameter portion (110, 111) and the large diameter portion and gradually increases in diameter from the small diameter portion (110, 111) toward the large diameter portion, the core shaft (100, 101) and the coil body being fixed at a portion of the core shaft excluding the tapered portion, characterized in that bending rigidity FR1 of the large diameter portion, bending rigidity FR2 of the small diameter portion (110, 111), and a length L of the tapered portion (130, 131) in an axial direction of the core shaft (100, 101) satisfy the following expressions and: FR 1 / FR 2 / L ≥ 10 1 ≤ L ≤ 3, wherein in the above expressions and, the unit of L is mm. the distal end portion of the core shaft includes: a small diameter portion (110, 111) that is continuous with the distal end fixing portion (401, 402), a large diameter portion that is positioned in a proximal end direction than the small diameter portion (110, 111) and has a larger outer diameter than a diameter of the small diameter portion (110, 111), and a tapered portion (130, 131) that is continuous with the small diameter portion (110, 111) and the large diameter portion and gradually increases in diameter from the small diameter portion (110, 111) toward the large diameter portion, a small diameter portion (110, 111) that is continuous with the distal end fixing portion (401, 402), a large diameter portion that is positioned in a proximal end direction than the small diameter portion (110, 111) and has a larger outer diameter than a diameter of the small diameter portion (110, 111), and a tapered portion (130, 131) that is continuous with the small diameter portion (110, 111) and the large diameter portion and gradually increases in diameter from the small diameter portion (110, 111) toward the large diameter portion, the core shaft (100, 101) and the coil body being fixed at a portion of the core shaft excluding the tapered portion, characterized in that bending rigidity FR1 of the large diameter portion, bending rigidity FR2 of the small diameter portion (110, 111), and a length L of the tapered portion (130, 131) in an axial direction of the core shaft (100, 101) satisfy the following expressions and: FR 1 / FR 2 / L ≥ 10 1 ≤ L ≤ 3, wherein in the above expressions and, the unit of L is mm.