A sieve device for insertion in a shaft has a connection for wastewater arriving in a supply device, which supply device is connected to a sieve surface of the sieve device for separating material to be separated from the wastewater. A worm conveyor transports the material to be separated out of the shaft. A fastening device is arranged in the shaft for the vertical fastening of the sieve device. The fastening device comprises a guide for the sieve device. An intersection is provided between the supply device and the sieve device. The guide positions the sieve device in front of the intersection when the sieve device is moved relative to the supply device into the shaft for purposes of mounting.