Patent ID: 7462838

Claim:
An electrostatic deflection circuit of an electronic beam measuring apparatus which outputs a deflection signal to an electrostatic deflector to deflect an electronic beam to scan on a sample, comprises: a deflection circuit for low magnification comprising a first operational amplifier of a first amplification factor which amplifies the deflection signal by the first operational amplifier; a deflection circuit for high magnification comprising a second operational amplifier of a second amplification factor which is lower than the first amplification factor, which amplifies the deflection signal by the second operational amplifier; and a switch circuit which switches to the deflection circuit for low magnification and outputs the deflection signal to the electrostatic deflector when a scan magnification of the electronic beam measuring apparatus is no more than a given value, and switches to the deflection circuit for high magnification and outputs the deflection signal to the electrostatic deflector when the scan magnification is over the given value.