A fastener member 10 is provided with a base portion 11 having a main surface 15, and a plurality of engaging members 12 provided upright on the main surface 15, in which mechanical coupling with a loop member 30 is achieved by causing the engaging members 12 to engage the loop member 30. The fastener member 10 is provided with an arm portion 13 disposed on the base portion 11 via a base connection portion 13a such that a tip side can pivot in a direction so as to approach the main surface 15, a claw portion 18 that is provided to the arm portion 13, and a hook-shaped protruding portion 14 provided to the base portion 11. The claw portion 18 and the hook-shaped protruding portion 14 latch onto one another when the fastener member 10 and the loop member 30 are coupled. The tip side of the arm portion 13 is positioned to a position opposite the main surface 15 away from the tips of the engaging portions 12 when the fastener member 10 and the loop member 30 are not coupled.