A method for providing a surface of a conductor rail (1, 1') used in electrolysis with an electric current supplier (6a, 6b, 6c, 6') made of silver or a silver-based alloy and having a contact surface having the electrical conductivity of silver or the silver-based alloy, the conductor rail being meant to be brought into an electrical contact through the electric current supplier (6a, 6b, 6c, 6') with a support rod (13, 13') used in an electrolysis basin, characterized by method steps according to which an upper surface of the conductor rail (1, 1') is provided with slots and teeth comprising inclinded surfaces, the slots being between the teeth or the conductor rail is provided with drillings for receiving support rods (13, 13'), and in that a) the material selected for the conductor rail (1, 1') is a aluminium-based alloy or aluminium; b) said surface of the conductor rail (1, 1') having an aluminium surface is heated and on top of the heated surface there is provided a zinc-based solder, which contains a substance having a higher affinity to oxygen than aluminium once the temperature of the aluminium surface reaches a temperature exceeding the melting temperature of the solder, the solder being spread in a molten state onto a surface area of a desired size of the aluminium surface so that a solder in a molten state is formed onto the surface, c) an aluminium oxide layer formed between aluminium and the molten solder is broken by mechanical treatment so that oxygen is released from the aluminium oxide layer, the oxygen reacting with the substance having a higher affinity to oxygen than aluminium present in the solder and forming together with said substance an oxide layer on the surface of the molten solder, and d) the electric current supplier (6a, 6b, 6c, 6') made of silver or a silver-based alloy is provided on top of the solder present on said surface area, the solder is allowed to solidify and the electric current supplier to become attached in place in the solidified solder. a) the material selected for the conductor rail (1, 1') is a aluminium-based alloy or aluminium; b) said surface of the conductor rail (1, 1') having an aluminium surface is heated and on top of the heated surface there is provided a zinc-based solder, which contains a substance having a higher affinity to oxygen than aluminium once the temperature of the aluminium surface reaches a temperature exceeding the melting temperature of the solder, the solder being spread in a molten state onto a surface area of a desired size of the aluminium surface so that a solder in a molten state is formed onto the surface, c) an aluminium oxide layer formed between aluminium and the molten solder is broken by mechanical treatment so that oxygen is released from the aluminium oxide layer, the oxygen reacting with the substance having a higher affinity to oxygen than aluminium present in the solder and forming together with said substance an oxide layer on the surface of the molten solder, and d) the electric current supplier (6a, 6b, 6c, 6') made of silver or a silver-based alloy is provided on top of the solder present on said surface area, the solder is allowed to solidify and the electric current supplier to become attached in place in the solidified solder.