A liquid blow molding apparatus, including: a nozzle configured to define a flow path for a liquid that includes an opening and closing port and a discharge port; a seal body configured to open and close the opening and closing port and includes a guide hole; and a rod configured to move in an axial direction while being guided by the guide hole, wherein the seal body includes a tubular-shaped extension portion configured to extend into the discharge port when the seal body closes the opening and closing port, and a tip surface of the extension portion is configured to have liquid repellency.