A pair of adjacent metal sheet piles, each pile comprising: first and second end flanges; and first and second joint portions formed at an edge of said first and second end flanges, respectively, each of said first and second joint portions, which are formed by bending inward, including a fitting groove formed therein, and a protrusion extending into the fitting groove, wherein the fitting grooves of said first and second joint portions of the same pile open in opposite directions, the cross-sections of the first and second joint portions are point-symmetric, said first and second end flanges of said sheet pile are connected to first and second webs, respectively, and the first and second webs are connected to each other via a central flange located therebetween, and said first and second joint portions are designed so that a center of a point of symmetry of a joint of the interfitted joint portions of the pair of the adjacent metal sheet piles is located on a centerline of said first and second end flanges, of the first and second sheet pile, respectively, in a thickness direction when one of the metal sheet piles is engaged with the adjacent metal sheet pile to form a pair of interfitted joint portions, wherein each of said metal sheet pile is hat-shaped in cross-section, and wherein each of said first and second joint portions includes a connecting portion, a bottom portion, and an engaging edge portion widening toward an end thereof, the connecting portion, the bottom portion and the engaging edge portion forming said fitting groove with a trapezoidal and tapered-off cross-section, and said protrusion is formed on a fitting groove side of the connecting portion. first and second end flanges; and first and second joint portions formed at an edge of said first and second end flanges, respectively, each of said first and second joint portions, which are formed by bending inward, including a fitting groove formed therein, and a protrusion extending into the fitting groove, wherein the fitting grooves of said first and second joint portions of the same pile open in opposite directions, the cross-sections of the first and second joint portions are point-symmetric, said first and second end flanges of said sheet pile are connected to first and second webs, respectively, and the first and second webs are connected to each other via a central flange located therebetween, and said first and second joint portions are designed so that a center of a point of symmetry of a joint of the interfitted joint portions of the pair of the adjacent metal sheet piles is located on a centerline of said first and second end flanges, of the first and second sheet pile, respectively, in a thickness direction when one of the metal sheet piles is engaged with the adjacent metal sheet pile to form a pair of interfitted joint portions, wherein each of said metal sheet pile is hat-shaped in cross-section, and wherein each of said first and second joint portions includes a connecting portion, a bottom portion, and an engaging edge portion widening toward an end thereof, the connecting portion, the bottom portion and the engaging edge portion forming said fitting groove with a trapezoidal and tapered-off cross-section, and said protrusion is formed on a fitting groove side of the connecting portion.