A vulcanization mold in which an annular mold for forming a tire tread of a pneumatic tire is split in a circumferential direction into a plurality of sector molds and the sector molds are each moved in directions toward a center and combined with each other to clamp a raw tire on an inner side to vulcanization mold the raw tire, each of the sector molds having blades implanted on a mold surface thereof, the blades being thin plate-like members extending in a tire widthwise direction and being used to form groove lines on the tire tread, each of the blades having a blade proximal end portion to be embedded into the sector mold, a blade distal end side thick portion expanded in a thicknesswise direction on the distal end side, and a blade connection portion that connects the blade proximal end portion and the blade distal end side thick portion to each other, wherein a full length of a protruding side that protrudes from the sector mold of the blade connection portion of the blade is shorter at the blades in the circumferential end portion side regions than at the blades in the circumferential central portion side region of the sector mold; characterized in that a multiplication value obtained by multiplying a sweep area that is a difference where a cross sectional area of the blade connection portion is subtracted from an area from the blade distal end side thick portion to the mold surface with a width equal to a maximum width of a thickness of the blade distal end side thick portion in a cross sectional shape perpendicular to the tire widthwise direction of the blade by a full length of a protruding side of the blade connection portion is smaller at the blades in the circumferential end portion side regions than at the blades in the circumferential central portion side region of the sector mold. each of the sector molds having blades implanted on a mold surface thereof, the blades being thin plate-like members extending in a tire widthwise direction and being used to form groove lines on the tire tread, each of the blades having a blade proximal end portion to be embedded into the sector mold, a blade distal end side thick portion expanded in a thicknesswise direction on the distal end side, and a blade connection portion that connects the blade proximal end portion and the blade distal end side thick portion to each other, wherein a full length of a protruding side that protrudes from the sector mold of the blade connection portion of the blade is shorter at the blades in the circumferential end portion side regions than at the blades in the circumferential central portion side region of the sector mold; characterized in that a multiplication value obtained by multiplying a sweep area that is a difference where a cross sectional area of the blade connection portion is subtracted from an area from the blade distal end side thick portion to the mold surface with a width equal to a maximum width of a thickness of the blade distal end side thick portion in a cross sectional shape perpendicular to the tire widthwise direction of the blade by a full length of a protruding side of the blade connection portion is smaller at the blades in the circumferential end portion side regions than at the blades in the circumferential central portion side region of the sector mold.