Temporary tightening tool for fastening member

A temporary tightening tool for a fastening member, which is used for temporarily tightening a fastening member that is a bolt or nut for fastening a tire wheel to a hub, comprising:

• a grip part for an operator to input torque, and
• a socket part formed at a tip of said grip part, into which a hexagonal columnar part formed at said fastening member is inserted, wherein:
• said socket part comprises:
• a leaf spring part which is pressed by a part of six side surfaces of said hexagonal columnar part to be elastically deformed outward in a radial direction of said hexagonal columnar part when said hexagonal columnar part is inserted in said socket part, and presses said part of said six side surfaces inward in the radial direction with restoring force to hold said hexagonal columnar part such that said hexagonal columnar part is clamped, and
• a torque transmission part which transmits torque to a side surface that is not pressed by said leaf spring part among said six side surfaces of said hexagonal columnar part when said torque is input into said grip part in a state where said hexagonal columnar part has been inserted in said socket part.