A method for assembling a steering system comprising: an intermediate shaft to which a turning force of a steering member is transmitted through a first end of the intermediate shaft via a steering shaft to which the steering member is coupled at a first end of the steering shaft; a first universal joint coupled to the first end of the intermediate shaft; and a second universal joint coupled to a second end of the intermediate shaft, wherein the first universal joint includes a first yoke coupled to the intermediate shaft and a second yoke paired with the first yoke, and the second universal joint includes a third yoke coupled to the intermediate shaft, a fourth yoke paired with the third yoke, and a shaft attachment portion coupled to the fourth yoke and via which a shaft is attached to the fourth yoke, and a bolt insertion hole is formed in the shaft attachment portion to allow the shaft to be clamped, characterized in that the second yoke includes: a tubular portion through which the steering shaft is inserted, a pair of clamping plates extending from the tubular portion and clamping the steering shaft via the tubular portion, and a pair of arm portions extending from the tubular portion in an axial direction thereof and facing each other across a central axis of the steering shaft at a position displaced from the position of arm portions of the first yoke by 90° along the central axis; and the tubular portion, the clamping plates, and the second arm portions are integrally formed, wherein the method comprises: when an angle (β) between the intermediate shaft and a shaft coupled to the second yoke is set to θ1, an around-axis angle (α) of the first yoke in a rotating direction around an axial direction is set to ω1 so that torsional rigidity of the intermediate shaft is highest or lowest when the steering member is located in the steering neutral position, and an angle (γ) between the intermediate shaft and the shaft coupled to the fourth yoke is set to θ2, adjusting a junction angle (ε) between the fourth yoke and the shaft attachment portion in the rotating direction to set an around-axis angle (φ) of the bolt insertion hole in the shaft attachment portion in the rotating direction to a preset angle ω2. an intermediate shaft to which a turning force of a steering member is transmitted through a first end of the intermediate shaft via a steering shaft to which the steering member is coupled at a first end of the steering shaft; a first universal joint coupled to the first end of the intermediate shaft; and a second universal joint coupled to a second end of the intermediate shaft, wherein the first universal joint includes a first yoke coupled to the intermediate shaft and a second yoke paired with the first yoke, and the second universal joint includes a third yoke coupled to the intermediate shaft, a fourth yoke paired with the third yoke, and a shaft attachment portion coupled to the fourth yoke and via which a shaft is attached to the fourth yoke, and a bolt insertion hole is formed in the shaft attachment portion to allow the shaft to be clamped, characterized in that the second yoke includes: a tubular portion through which the steering shaft is inserted, a pair of clamping plates extending from the tubular portion and clamping the steering shaft via the tubular portion, and a pair of arm portions extending from the tubular portion in an axial direction thereof and facing each other across a central axis of the steering shaft at a position displaced from the position of arm portions of the first yoke by 90° along the central axis; and the tubular portion, the clamping plates, and the second arm portions are integrally formed, wherein the method comprises: when an angle (β) between the intermediate shaft and a shaft coupled to the second yoke is set to θ1, an around-axis angle (α) of the first yoke in a rotating direction around an axial direction is set to ω1 so that torsional rigidity of the intermediate shaft is highest or lowest when the steering member is located in the steering neutral position, and an angle (γ) between the intermediate shaft and the shaft coupled to the fourth yoke is set to θ2, adjusting a junction angle (ε) between the fourth yoke and the shaft attachment portion in the rotating direction to set an around-axis angle (φ) of the bolt insertion hole in the shaft attachment portion in the rotating direction to a preset angle ω2.