PURPOSE: To improve S/N by controlling potential of an end of a charging circuit and charging intermittently a condenser for a condenser that integrates AC noise included in the signal voltage.

CONSTITUTION: Signal voltage Vi is applied to the base of a transistor (TR)16; and a discharge current i1 is integrated by a condenser 17 for a picture element period. At the end of a picture element section, a nodal point 17A is charged through a rectifier cell 18 and a resistance (R)19. The signal voltage is outputted to an output terminal 20 during the charging period. A discharging circuit 26 consists of a TR16 and a TR15, and a charging circuit 25 consists of an R19, TR21 and R22. A rectifier cell 23 that connects the emitter of the TR21 and a clock power source is added. Thus, S/N of the solid state image pickup device is improved without subjecting to the fluctuation of clock potential.