PURPOSE: To shorten wait time from attaching of a detector to measurement owing to downsizing of the detector itself, improve integration accuracy and measurement accuracy owing to automatic injection of sample solution, simplify replenishment of electrolytic solution and cleaning of an electrode, enable stable and continuous measurement owing to constant control of a hold-up amount of the electrolytic solution, downsize the detector and improve measurement sensitivity without limitation of the hold-up amount accompanying the sample injection.

CONSTITUTION: A rotating type coulometric analyzing detector comprises a detector body 1 for coulometric analysis having a detecting pole and an opposite pole made of a porous conductive body with electrolytic solution impregnated placed at both sides with a partition film interposed and a rotating means 16 for rotating the detector. It further comprises means 10,11 for supplying sample and electrolytic solution to the detector and a means 14 for detecting which supplies electric power to the above detector and detects at least one or more changes of voltage, current and electric amount.