A connection device comprising: a first braided conductor having a tubular shape; a second braided conductor having a tubular shape; a tubular member having a first opening end and a second opening end, the tubular member having conductivity; a first annular member configured to be fixed to the first opening end in a state that the first braided conductor is sandwiched coaxially between the first annular member and an outer peripheral surface of the first opening end; and a second annular member configured to be fixed to the second opening end in a state that the second braided conductor is sandwiched coaxially between the second annular member and an outer peripheral surface of the second opening end, wherein the first braided conductor and the second braided conductor are conductively connected to each other through the tubular member, characterized in that a first annular electric wire holder provided between a first inner peripheral surface of the tubular member and a first electric wire which is covered with the first braided conductor to hold the first electric wire when the first electric wire is inserted through the tubular member; a second annular electric wire holder provided between a second inner peripheral surface of the tubular member and a second electric wire which is covered with the second braided conductor to hold the second electric wire when the second electric wire is inserted through the tubular member; and an annular water stop ring sandwiched between the first electric wire holder and the second electric wire holder in a tubular axial direction of the tubular member. a first braided conductor having a tubular shape; a second braided conductor having a tubular shape; a tubular member having a first opening end and a second opening end, the tubular member having conductivity; a first annular member configured to be fixed to the first opening end in a state that the first braided conductor is sandwiched coaxially between the first annular member and an outer peripheral surface of the first opening end; and a second annular member configured to be fixed to the second opening end in a state that the second braided conductor is sandwiched coaxially between the second annular member and an outer peripheral surface of the second opening end, wherein the first braided conductor and the second braided conductor are conductively connected to each other through the tubular member, characterized in that a first annular electric wire holder provided between a first inner peripheral surface of the tubular member and a first electric wire which is covered with the first braided conductor to hold the first electric wire when the first electric wire is inserted through the tubular member; a second annular electric wire holder provided between a second inner peripheral surface of the tubular member and a second electric wire which is covered with the second braided conductor to hold the second electric wire when the second electric wire is inserted through the tubular member; and an annular water stop ring sandwiched between the first electric wire holder and the second electric wire holder in a tubular axial direction of the tubular member.