The present invention is configured such that a guide bar for supporting a diagnostic reagent paper includes a groove and the groove prevents the diagnostic reagent paper from being supported by a guide member in a section where knives using a shear force cut the diagnostic reagent paper, whereby a pressed line generated when the guide member presses the diagnostic reagent paper due to a cutting force by the knives is prevented from being formed on a strip so as to eliminate defects of the strip. In particular, the present invention is configured such that the guide member is installed to be disposed to pass through a space between a first shaft and a second shaft, each formed by repeatedly arranging two knives facing each other and one space, so as to guide the diagnostic reagent paper, whereby a section through which the diagnostic reagent paper passes has a substantially rectangular shape. Therefore, not only can the diagnostic reagent paper cut into strips accurately by a blade, but also the cut strips have no defects such as bending, entangling, or twisting.