Abstract: A particle analytical device comprises a light receiving part that receives the scattered light emitted from the particle group and that outputs an electric current signal, a data processing part that processes data based on time series data of a number of pulses obtained by the electric current signal, and a control part that halts a movement of the light receiving part in case that the overcurrent is detected based on the electric current signal and that restarts the movement of the light receiving part after a predetermined time passes and is characterized by that the data processing part holds the time series data until the light receiving part is halted and processes the data after the movement of the light receiving part is restarted by the use of the held time series data and the time series data obtained after the restart.

Abstract: A dynamic scattering type particle diameter distribution measurement device comprising a light receiving part that receives scattered light emitted from the particle group and that outputs a pulse signal in accordance with a photon number of the received light, a plurality of multibit counters that receives the pulse signal while a gate is open and counts a pulse number, a correlator that obtains auto-correlation data from time series data of the pulse number, and a calculation part that calculates particle diameter distribution based on the auto-correlation data, a gate time changing part that changes gate time once or a plurality of times and a gate time judging part that compares mutually the differences between the maximum value and the minimum value of the auto-correlation data output every time the gate time is changed and judges the gate time corresponding to the maximum difference as a recommended value.