A connection portion between a single-core line electrical line and a stranded electrical line is prevented from bulging in the diameter direction. A conductor exposed portion is formed on an end portion of the single-core line electrical line, and an individual wire exposed portion is formed on an end portion of the stranded electrical line. A collapsed portion is formed on the conductor exposed portion, and a connection block portion is formed by welding together individual wires of the individual wire exposed portion. The compressed portion and the connection block portion are joined in an overlapping state. At this time, the collapsed portion is bent such that a level difference is formed in the diameter direction such that the single-core line electrical line and the stranded electrical line are joined approximately coaxially.