PURPOSE: To detect the height of toner in a bottle by dividing the bottle wherein afterimage toner is collected into a bottle main body and a sensor-fitting housing at the upper part of the bottle, and by fitting a pressure-sensitive element to the housing.

CONSTITUTION: A toner bottle 9 consists of a cylindrical sensor housing 10 having a small diameter and a bottle main body 11 equipped with a detachable upuper-end neck part 11a. Then, a full-up sensor 12 is added to the sensor housing 10, and a pressure-sensitive element 12a is provided being exposed to the inside of the sensor housing 10. When toner is collected in the toner bolt main body 11 more than a constant quantity and the pressure-sensitive element 12a is applied with the deposit pressure of the toner, the full-up sensor 12 operates to send a detection signal. Since the bottle is divided, the bottle is replaced easily without reference to the pressure-sensitive element and the reliability is improved by reducing the capacity of the sensor housing 12.