A cover structure of a vehicle-body outer panel connection portion, the cover structure comprising: a first vehicle-body outer panel that is made of a steel sheet and has a surface of a vehicle body; a second vehicle-body outer panel that is made of a steel sheet and has a surface which is continuous to the surface; and a cover member that covers a stepped portion having a height difference by a panel thickness (tr) resulted after an end portion of the second vehicle-body outer panel is connected in an overlapping manner to an end portion of the first vehicle-body outer panel, wherein the stepped portion is located in a connection recess portion which is formed by connecting a second bent portion, in which the end portion of the second vehicle-body outer panel is deformed centerward in a vehicle width direction, to a first bent portion in which the end portion of the first vehicle-body outer panel is deformed centerward in the vehicle width direction, the cover member is attached to the connection recess portion and is comprised of a cover body of a thermoplastic resin and a bonding film layer which is applied to an attachment surface forming an inner surface of the cover body facing the first vehicle-body outer panel and the second vehicle-body outer panel, the cover body is comprised of a thick-walled body portion formed with a thickness corresponding to a depth of the connection recess portion at a center thereof and a lip portion which is continuous to the body portion, the body portion is configured by forming the outer surface of the cover body in a convex curved shape, and the lip portion has a wall thickness which gradually decreases from the body portion toward fringes (57, 58) of the cover body, and, of the fringes (57, 58), a fringe portion (66, 67) of a door seal contacting portion (64, 65) coming in contact with a seal member (61, 62) provided in a door (22, 23) is formed with a step-free thickness in relation to the first vehicle-body outer panel and the second vehicle-body outer panel. a first vehicle-body outer panel that is made of a steel sheet and has a surface of a vehicle body; a second vehicle-body outer panel that is made of a steel sheet and has a surface which is continuous to the surface; and a cover member that covers a stepped portion having a height difference by a panel thickness (tr) resulted after an end portion of the second vehicle-body outer panel is connected in an overlapping manner to an end portion of the first vehicle-body outer panel, wherein the stepped portion is located in a connection recess portion which is formed by connecting a second bent portion, in which the end portion of the second vehicle-body outer panel is deformed centerward in a vehicle width direction, to a first bent portion in which the end portion of the first vehicle-body outer panel is deformed centerward in the vehicle width direction, the cover member is attached to the connection recess portion and is comprised of a cover body of a thermoplastic resin and a bonding film layer which is applied to an attachment surface forming an inner surface of the cover body facing the first vehicle-body outer panel and the second vehicle-body outer panel, the cover body is comprised of a thick-walled body portion formed with a thickness corresponding to a depth of the connection recess portion at a center thereof and a lip portion which is continuous to the body portion, the body portion is configured by forming the outer surface of the cover body in a convex curved shape, and the lip portion has a wall thickness which gradually decreases from the body portion toward fringes (57, 58) of the cover body, and, of the fringes (57, 58), a fringe portion (66, 67) of a door seal contacting portion (64, 65) coming in contact with a seal member (61, 62) provided in a door (22, 23) is formed with a step-free thickness in relation to the first vehicle-body outer panel and the second vehicle-body outer panel.