To provide a thumbtack having a safety feature superior to the prior art.

The thumbtack assembly comprises two thumbtacks joined to each other and has the following requirements (1)-(4). (1) The thumbtack 10 is composed of a first surface 102 with a pressurizing face formed, a second surface 106 with a needle protruding, and a barrel 108 connecting the first and the second surface. (2) The barrel is further provided with a housing section 110 for housing the opposite needle. (3) The two thumbtacks are provided with a recessed part or a projected part 112, 112' at least in one place of a portion selected from a group consisting of the first surface, the second surface and the barrel, facilitating the grasp of the position of the housing section. (4) The thumbtack assembly is formed by housing the needle of the opposite thumbtack in the housing section of the barrel of one thumbtack.