A strain inspection device of a printed circuit board (PCB) which is easily cracked or damaged by external pressure (force) applied to the PCB while the PCB is being assembled, and an attaching method thereof. The strain inspection device of a printed circuit board (PCB) includes a fixing member; and a damage indicator fixed to the PCB by the fixing member, having a crack guide through hole, and cracked or damaged along a corner of the crack guide through hole due to deformation of the PCB.