Method for monitoring and supervising the lubricant content of elevator ropes in an elevator, which comprises at least a hoisting machine provided with a drive motor, said hoisting machine comprising at least a traction sheave, around which one or more elevator ropes are fitted side-by-side, which ropes move under the effect of friction along with the rotational movement of the traction sheave and at the same time move the elevator car, characterized in that the lubricant content of the elevator ropes is monitored and supervised by the aid of a measuring device by collecting in the measuring device the metal dust and/or rust detaching in connection with wear of the traction sheave and of the elevator ropes during operation of the elevator and by letting the metal dust and/or rust switch on an alarm about a lubricant content of the elevator ropes that is too low, whereby - the metal dust and/or rust detaching in connection with wear of the traction sheave and of the elevator ropes during operation of the elevator is collected on the surface of a permanent magnet that is in the measuring device to electrically close an open alarm circuit connected to the control and operating system of the elevator, or - the metal dust and/or rust detaching in connection with wear of the traction sheave and of the elevator ropes during operation of the elevator is collected on the surface of the permanent magnet that is in the measuring device and the pattern formed by, and/or the amount of, the metal dust and/or rust is measured optically and an alarm is effected in the control and operating system of the elevator on the basis of a change in the pattern and/or amount, or - the metal dust and/or rust detaching in connection with wear of the traction sheave and of the elevator ropes during operation of the elevator is collected on a permanent magnet that is in the measuring device and the magnetic field of the measuring device is measured and also an alarm is effected in the control and operating system of the elevator on the basis of a change in the value of the magnetic field. - the metal dust and/or rust detaching in connection with wear of the traction sheave and of the elevator ropes during operation of the elevator is collected on the surface of a permanent magnet that is in the measuring device to electrically close an open alarm circuit connected to the control and operating system of the elevator, or - the metal dust and/or rust detaching in connection with wear of the traction sheave and of the elevator ropes during operation of the elevator is collected on the surface of the permanent magnet that is in the measuring device and the pattern formed by, and/or the amount of, the metal dust and/or rust is measured optically and an alarm is effected in the control and operating system of the elevator on the basis of a change in the pattern and/or amount, or - the metal dust and/or rust detaching in connection with wear of the traction sheave and of the elevator ropes during operation of the elevator is collected on a permanent magnet that is in the measuring device and the magnetic field of the measuring device is measured and also an alarm is effected in the control and operating system of the elevator on the basis of a change in the value of the magnetic field.