A synthetic amorphous silica powder which is obtained by subjecting silica as raw material to granulation and firing, characterized in that: the particle diameter (DV50) at a cumulative frequency of 50% in the volume particle size distribution is greater than 72 micrometers and less than 509 micrometers; the cumulative frequency of having particle size below 45micrometers in the volume particle size distribution is below 1.8%; if the difference value between the particle size DV90 of having cumulative frequency 90% in the volume particle size distribution and that of DV10 having cumulative frequency 10% in the volume particle size distribution is divided by the particle size DV50 of having cumulative frequency 50% in the volume particle size distribution, the resultant value is above 0.79 and below 1.40; FNL/FNS is above 0.3; volume density is above 0.75g/cm3 and below 1.5g/cm3.