A connection terminal (10A, 10B; 110A, 110B; 210A, 210B) comprising: a tubular electric wire connection portion (11, 111, 211) which is configured to be tightened and crimped to an end portion of an electric wire (20A, 20B); a tubular intermediate portion (13, 113, 213) which comprises one end continuously formed at one open end of the electric wire connection portion (11, 111, 211) and which has a cross-sectional shape larger than a cross-sectional shape of the electric wire connection portion (11, 111, 211); a tubular terminal connection portion (15, 115, 215) which is continuously formed at another end of the intermediate portion (13, 113, 213) and which has a cross-sectional shape larger than the cross-sectional shape of the intermediate portion (13, 113, 213); and a terminal contact portion which protrudes inwardly from the terminal connection portion (15, 115, 215); characterized in that the intermediate portion (13, 113, 213) is insertable into a terminal connection portion (15, 115, 215) of another connection terminal (10A, 110A, 210A) having same shape and dimension as the connection terminal (10B, 110B, 210B) so as to contact a terminal contact portion of said other connection terminal (10A, 110A, 210A) and to electrically connect the connection terminal (10B, 110B, 210B) and said other connection terminal (10A, 110A, 210A) and in that said end portion of the electrical wire (20A, 20B) is insertable into the tubular electric wire connection portion (11, 111, 211) from an electric wire connection side and from a terminal connection portion side of the connection terminal (10A, 10B; 110A, 110B; 210A, 210B) to be tightened and crimped to the tubular electric wire connection portion (11, 111, 211). a tubular electric wire connection portion (11, 111, 211) which is configured to be tightened and crimped to an end portion of an electric wire (20A, 20B); a tubular intermediate portion (13, 113, 213) which comprises one end continuously formed at one open end of the electric wire connection portion (11, 111, 211) and which has a cross-sectional shape larger than a cross-sectional shape of the electric wire connection portion (11, 111, 211); a tubular terminal connection portion (15, 115, 215) which is continuously formed at another end of the intermediate portion (13, 113, 213) and which has a cross-sectional shape larger than the cross-sectional shape of the intermediate portion (13, 113, 213); and a terminal contact portion which protrudes inwardly from the terminal connection portion (15, 115, 215); characterized in that the intermediate portion (13, 113, 213) is insertable into a terminal connection portion (15, 115, 215) of another connection terminal (10A, 110A, 210A) having same shape and dimension as the connection terminal (10B, 110B, 210B) so as to contact a terminal contact portion of said other connection terminal (10A, 110A, 210A) and to electrically connect the connection terminal (10B, 110B, 210B) and said other connection terminal (10A, 110A, 210A) and in that said end portion of the electrical wire (20A, 20B) is insertable into the tubular electric wire connection portion (11, 111, 211) from an electric wire connection side and from a terminal connection portion side of the connection terminal (10A, 10B; 110A, 110B; 210A, 210B) to be tightened and crimped to the tubular electric wire connection portion (11, 111, 211).