To clarify the effects of the vertical stress along the borehole on the hydraulic fracture formation, we conducted hydraulic fracturing experiments using the fracturing fluids of the water and the super critical carbon dioxide. A borehole was bored perpendicular to the weak plane of the rock, and horizontal stresses of 5 and 3 MPa and a vertical stress of 12 MPa were applied. The obtained results were compared with the results obtained at a lower applied vertical stress of 1 MPa. The total length of the fractures measured at the specimen surfaces for the vertical stress of 12 MPa tended to be smaller than that for a vertical stress of 1 MPa. This suggests that the horizontally oriented pores and microcracks were compressed by the high vertical stress and that the infiltration of the fracturing fluids significantly affected fracture propagation.