A suction-attachment structure includes an electrically conducting unit and a suction-attaching member. The suction-attaching member includes a base. The base has an edge from which a wall extends. The wall has an upper end forming an attaching face. The electrically conducting unit is coupled to the base of the suction-attaching member. The attaching face formed at the upper end of the wall defines a suction-attaching configuration to allow the suction-attaching member to securely hold the electrically conducting unit in position. As such, the electrically conducting unit is prevented from displacing during an operation of detection and contact engagement with a surface layer of a human body can be securely maintained for carrying out detection of physiological signals.
