To provide a web-forming apparatus by which jet of pulp slurry is used for web formation in good yield, and which efficiently forms a high-quality web while allowing the web to have a uniform thickness by stabilizing the thickness of the jet in the width direction.

The web-forming apparatus has a flow box 101 for jetting a paper feedstock, and a pair of nets 102 and 103 for forming paper by traveling while receiving the paper feedstock jetted from the flow box 101 and nipping the received paper feedstock. Sucking chambers 221a and 221c for instantly sucking water from the paper feedstock grounded on each of the back surfaces of the pair of the nets 102 and 103 are installed therein.