Abstract: A detecting apparatus of a development cartridge used with an image forming machine which can perform a printing process after detecting whether an appropriate development cartridge is mounted. The detecting apparatus includes a pressing portion formed on a lower surface of the development cartridge, an operation member disposed in the guiding portion to unidirectionally pivot by a predetermined angle by the pressing portion when the development cartridge is mounted on the guiding portion, and a sensor operating when the operation member pivots by a predetermined angle, wherein the detecting apparatus recognizes that the development cartridge is mounted when the sensor operates. The operation member includes a detecting portion pressed by the pressing portion, and a rotation shaft to support the detecting portion to pivot by a predetermined angle, and the sensor is operated by the detecting portion.