To provide thumbtacks having greater safety than any thumbtacks produced using conventional techniques.

A thumbtack assembly is provided with the following requirements (1)-(4). (1) The thumbtacks is equipped with: a first surface 102 that forms a pressurizing surface; a second surface 106 that projects a needle 104 in the vertical direction relating to the first surface 102; and a trunk 108 that couples the first and second surfaces. (2) The trunk 108 has an accommodating part 110 that accommodates the other needle 104'. (3) The accommodating part 110 is provided on the second surface 106 and at the end of the trunk 108, and opens toward the outside peripheral direction. (4) In the accommodating part 110 of the trunk of one of the thumbtacks, the needle of the other thumbtack is accommodated, and two thumbtacks are coupled so that the second surfaces 106, 106' substantially are mated with each other to form the thumbtack assembly.