A method for crimping a terminal to an aluminum electric wire comprising: preparing a terminal having an electric connecting portion which is configured to be connected with a mating terminal at a front end side thereof, and a conductor crimping portion which is configured to be crimped to a conductor of an electric wire configured to be connected therewith by being bent inward to be crimped at a rear end side thereof, preparing an aluminum electric wire having a conductor made of aluminum or an aluminum alloy as the electric wire configured to be connected with the conductor crimping portion ; and crimping the conductor crimping portion to the conductor of the aluminum electric wire by bending the conductor crimping portion inwards so as to embrace the conductor in a state that the conductor of the aluminum electric wire is inserted into an interior of the conductor crimping portion of the crimp terminal , wherein at least an inner surface of the conductor crimping portion is plated with a metal whose hardness is lower than a hardness of a metal of a terminal base material , and a thickness of the metal applied to plate the inner surface is set to be in a range from 2.1 μm to 5.0 μm, characterized in that a thickness of the metal applied to plate the inner surface of the conductor crimping portion is thicker than a thickness of the metal applied to plate an inner surface of the electric connection portion ; the aluminum electric wire has an insulated sheathing configured to be crimped with a sheathing crimping portion of the terminal ; and the electric connecting portion , the conductor crimping portion and the sheathing crimping portion are configured so as to include a common bottom plate part . preparing a terminal having an electric connecting portion which is configured to be connected with a mating terminal at a front end side thereof, and a conductor crimping portion which is configured to be crimped to a conductor of an electric wire configured to be connected therewith by being bent inward to be crimped at a rear end side thereof, preparing an aluminum electric wire having a conductor made of aluminum or an aluminum alloy as the electric wire configured to be connected with the conductor crimping portion ; and crimping the conductor crimping portion to the conductor of the aluminum electric wire by bending the conductor crimping portion inwards so as to embrace the conductor in a state that the conductor of the aluminum electric wire is inserted into an interior of the conductor crimping portion of the crimp terminal , wherein at least an inner surface of the conductor crimping portion is plated with a metal whose hardness is lower than a hardness of a metal of a terminal base material , and a thickness of the metal applied to plate the inner surface is set to be in a range from 2.1 μm to 5.0 μm, characterized in that a thickness of the metal applied to plate the inner surface of the conductor crimping portion is thicker than a thickness of the metal applied to plate an inner surface of the electric connection portion ; the aluminum electric wire has an insulated sheathing configured to be crimped with a sheathing crimping portion of the terminal ; and the electric connecting portion , the conductor crimping portion and the sheathing crimping portion are configured so as to include a common bottom plate part . <EOS>