Provided is an in-tank tube excellent in pressure-resisting performance. The in-tank tube is an in-tank tube (1) for an automotive fuel of a monolayer structure, the in-tank tube (1) for an automotive fuel being installed in a fuel tank (2) and having a construction that absorbs displacement of the fuel tank (2) and vibration of a fuel pump (5). Further, the in-tank tube (1) for an automotive fuel is formed into a monolayer structure formed of a resin material using an aliphatic polyamide resin as a main component, and has the following pressure-resisting characteristic (X): (X) when silicone oil is charged as a pressurizing medium into the in-tank tube immersed in a test liquid (Fuel C:methanol=85:15 (volume basis)) at 80° C. for 168 hours, both ends of the in-tank tube are each blocked with a test pipe, and a pressure test is performed at a rate of pressure increase of 1.0 MPa/min and room temperature, a pressure (burst pressure) at which the in-tank tube bursts or the test pipe disconnects is 2.8 MPa or more.