an electrical wire connection device is provided with : a shield shell , one end side having a connection part for inserting an electrical wire , the other end side having a cap part that can be mounted on a casing ; a grommet including a soft material , having formed at one end side an extension cylinder part through which an electrical wire can be passed , and having formed at the other end side a skirt part fitted into the shield shell from the connection part side and fitted to the outer peripheral surface of a step part ; and a grommet protective member formed of material harder than the grommet and arranged surrounding the skirt part from the outer peripheral surface side , a flange part being formed on the inner peripheral surface of the grommet protective member and pressing against the outer peripheral surface of the grommet .