To provide a break-off spout of excellent durability increased in connection strength between a sealing cap and a spout cylinder part without the separated sealing cap slipping into and being caught at an effusion port formed by breaking.

The break-off spout includes a joint part 11 fixable to a container; the spout cylinder part 12 extending upward from the joint part; and the sealing cap 14 integrally formed at the tip of the effusion port 12a of the spout cylinder part through a thin-walled part 13 that can be broken off. The sealing cap has a knob part 14a provided projecting outward, and the inner surface of the knob part and the outer peripheral surface of the spout cylinder part are connected to each other through a breakable bridge 14b. The outer peripheral surface of the spout cylinder part has inclined guides 12b provided on both sides of the bridge. When unsealing the sealing cap, the knob part is rotated to break the thin-walled part and the bridge, and the broken bridge is guided upward along the inclined guide parts to separate the sealing cap from the effusion port tip of the spout cylinder part.