valve shown in fig1 fig4 b shows that smd becomes less than 100 u03bcm and the fuel atomization can be obtained effectively if it has been found that the diameter d smaller than 0 25 mm such as 0 15 mm with as many orifices as possible can increase the surfaces of the fuel in contact with air thereby increasing the atomization the inside diameter of the conical surface 31a of the valve seat 30 decreases as the surface approaches the perforated surface 33 of the orifice plate 32 fig4 c shows that a distance h of the valve seat surface 31b from the perforated surface 33 is shorter than 4d which is expressed as follows the orifice plate 32 has twelve orifices 32a and 32b formed on the area of the perforated surface defining the fuel chamber 35 as shown in fig2 a six inner orifices 32a are disposed on an imaginary inner circle whose diameter is dh0 as shown in fig1 at equal intervals and six outer orifices 32b are disposed on an imaginary outer circle whose diameter is dh1 as shown in fig1 at equal intervals so that each concentric circle of the inner and outer orifices 32a 32b having the same diameter is disposed to be in contact with the concentric circles of the adjacent orifices the number of inner orifices 32a and the number of the outer orifices are the same and the orifices 32a and 32b are disposed to be symmetrical with respect to a line across orifices disposed opposite sides of the perforated surface 33.