Abstract: There is described a level-indicating device provided with a mounting the device in a wall of a bunker, tank or other container, a system for drive motor mounted to be freely rotatable about the axis thereof, an oscillating transmission unit connected to the drive motor, with an output shaft and a vane mounted on said shaft, whereby the drive motor is provided with switching means to generate a signal and to cut the motor off when the vane meets a resistance. Sealing means are provided for the sealing between the rotatable vane shaft and the mounting. The transmission unit is so designed as to cause a swinging motion of the vane due to the drive motor rotation, while the sealing means comprise a completely closed flexible sealing member which is positively connected on the one side to the vane shaft and on the other side to the mounting.