Proposed is an outer cylindrical spring pin including a compression spring (30), and an integrated upper probe (10) integrally provided with an upper probe portion (11) for contacting the outside, and with two upper probe side wall portions (12) which extend from the upper probe portion (11) and which surround two side surfaces facing each other, among four side surfaces of the compression spring (30). The spring pin further includes an integrated lower probe (20) integrally provided with a lower probe portion (21) for contacting the outside, and with two lower probe side wall portions (22) which extend from the lower probe portion (21) and which surround other two side surfaces between the two side surfaces. When an external force is applied, the upper and lower probe side wall portions (12 and 22) are capable of being slid on each other while being in contact with each other.