To provide a level position detecting device which detects the level position of flowing liquid and detects the accurate level position irrespective of the viscosity of detected liquid.

This level position detecting device 91 has an arm-shaped actuator 92 of which the tip 92a is immersed in liquid developer in a storage tank and the other end is attached to a shaft 94 projecting from a box 93 which stores a microswitch. In accordance with a change of the level position of the liquid developer, when the tip of the actuator is pushed by liquid stream (a) and is circularly rotated and moved by centering the shaft, the shaft is also rotated in the circumferential direction and, when the tip of the actuator is stopped on the detection position corresponding to the level position, the shaft is also stopped and the attachment and detachment to the contact which takes part in ON/OFF of switch is performed in the box.