Method and device for ensuring the safety of a low-altitude flight of an aircraft.The device (1) comprises a recording means (8) corresponding to an operation critical instrument for recording, during a low-altitude flight, one part at least of the lateral trajectory of the flight trajectory situated ahead of the current position of the aircraft, a monitoring means (11) for monitoring, during a low-altitude flight, the availability at least of said lateral trajectory, and a guidance system (3) for taking the aircraft up to a safe altitude, taking into account said part of the trajectory recorded by said recording means (8), when said monitoring means (11) has detected a loss of said lateral trajectory.