A terminal crimping method for crimping a terminal onto an aluminum electric-wire to be arranged in a vehicle, the aluminum electric-wire including: an electrical conductor part comprising numerous strands; and a coating part coated on the electrical conductor part; the method comprising the steps of: preparing the aluminum electric-wire; preparing the terminal having a wire barrel to be crimped onto the electrical conductor part of the aluminum electric-wire, wherein the wire barrel is of the open barrel type; crimping the terminal onto the aluminum electric-wire thereby deforming the barrel end portions by crimping pressure and urging the wire barrel tip ends of the terminal into between strands of the electrical conductor part of the aluminum electric-wire, wherein the compressed ratio of the conductor part of the aluminum electric-wire has an upper limit value of 70% in terms of the ratio of the cross-sectional area of the conductor part of the aluminum electric-wire at the crimped portion related to the cross-sectional area of the conductor part of the aluminum electric-wire before crimping, characterized in that the electrical conductor part to be crimped has a cross sectional area of 1.5mm 2; and said compressed ratio has a lower limit value where the lower limit value is selected to obtain a terminal crimping tensile strength in terms of a retaining force between the terminal and said aluminum electric-wire of at least 100N. an electrical conductor part comprising numerous strands; and a coating part coated on the electrical conductor part; the method comprising the steps of: preparing the aluminum electric-wire; preparing the terminal having a wire barrel to be crimped onto the electrical conductor part of the aluminum electric-wire, wherein the wire barrel is of the open barrel type; crimping the terminal onto the aluminum electric-wire thereby deforming the barrel end portions by crimping pressure and urging the wire barrel tip ends of the terminal into between strands of the electrical conductor part of the aluminum electric-wire, wherein the compressed ratio of the conductor part of the aluminum electric-wire has an upper limit value of 70% in terms of the ratio of the cross-sectional area of the conductor part of the aluminum electric-wire at the crimped portion related to the cross-sectional area of the conductor part of the aluminum electric-wire before crimping, characterized in that the electrical conductor part to be crimped has a cross sectional area of 1.5mm 2; and said compressed ratio has a lower limit value where the lower limit value is selected to obtain a terminal crimping tensile strength in terms of a retaining force between the terminal and said aluminum electric-wire of at least 100N. preparing the aluminum electric-wire; preparing the terminal having a wire barrel to be crimped onto the electrical conductor part of the aluminum electric-wire, wherein the wire barrel is of the open barrel type; crimping the terminal onto the aluminum electric-wire thereby deforming the barrel end portions by crimping pressure and urging the wire barrel tip ends of the terminal into between strands of the electrical conductor part of the aluminum electric-wire, wherein the compressed ratio of the conductor part of the aluminum electric-wire has an upper limit value of 70% in terms of the ratio of the cross-sectional area of the conductor part of the aluminum electric-wire at the crimped portion related to the cross-sectional area of the conductor part of the aluminum electric-wire before crimping, characterized in that the electrical conductor part to be crimped has a cross sectional area of 1.5mm 2; and said compressed ratio has a lower limit value where the lower limit value is selected to obtain a terminal crimping tensile strength in terms of a retaining force between the terminal and said aluminum electric-wire of at least 100N.