To mitigate shearing force and prevent a fastening defect of a mounting member by interposing a sliding means between the bearing surface of a mounting member and the bearing surface of a fastening member.

A bolt 5 of a fastening member is pushed and passed through holes 4 of mounting members 1, 2, 3. The mounting members 1, 2, 3 are fastened by the screwing of a bolt 5 onto a male screw 5b by a nut 6. The bearing surface 5a of the bolt 5 and the bearing surface 6a of the nut 6 are abutted on the bearing surfaces 2a, 3a of the mounting members 2, 3 and holding power of the bolt 5 and the nut 6 is displayed by frictional force. When side pressing force works in the axial direction, the mounting member 1 moves in the direction of the arrow (p) and presses the side part of the bolt 5. When the bolt 5 receives fixed pressing force or more, the bearing surface 6a screwed onto the male screw 5b slides in space between the bearing surface 2a by a sliding means 7, together with the mounting member 1 or with the bolt 5 and the mounting members 1, 2, 3 being against frictional force. Therefore, the bolt 5 generates inclination and slides, a part of pressing force due to the arrow (p) is absorbed and shearing force is not applied to the bolt 5.