A sealing structure of a part of a center-pillarless automotive vehicle at which part a first end part of a hinged door, a second end part of a sliding door, and a main weather strip which is provided along a body opening periphery are caused to abut each other, comprising: - a first sealing member which is provided to an upper part of the first end part, and - a second sealing member which is provided to an upper part of the second end part, wherein: - the first sealing member being configured such that a first inner wall, which is located on a vehicle-interior side, and a second inner wall, which is brought into elastic contact with the second sealing member, are connected to each other via a first curved wall, which is curved so as to protrude to a second-sealing-member side, - the second sealing member being configured such that a third inner wall, which is located on the vehicle-interior side, and a second curved wall, which is curved in a case where the second curved wall is brought into elastic contact with the first sealing member, are connected to each other via a connection part, which is tapered as the connection part extends toward the first sealing member, - an end part of the third inner wall, which end part is located on a connection-part side, being thinner than the other part of the third inner wall, - at least a tip of the connection part being located on a vehicle-interior side of a surface of the third inner wall which surface is located on the vehicle-interior side, and - the first curved wall and the second curved wall being brought into contact with each other in a case where the first end part and the second end part are caused to abut each other, characterized in that - the end part of the third inner wall, which end part is located on the connection-part side, being gradually decreased in thickness toward the tip of the connection part, - the end part, located on the connection-part side, of the third inner wall having a vehicle-exterior-side side surface that is curved so as to protrude to a vehicle-exterior side, and - the second curved wall being curved so as to, on a rear side, protrude to the vehicle-exterior side and so as to, on a front side, be depressed to the vehicle-exterior side. - a first sealing member which is provided to an upper part of the first end part, and - a second sealing member which is provided to an upper part of the second end part, - the first sealing member being configured such that a first inner wall, which is located on a vehicle-interior side, and a second inner wall, which is brought into elastic contact with the second sealing member, are connected to each other via a first curved wall, which is curved so as to protrude to a second-sealing-member side, - the second sealing member being configured such that a third inner wall, which is located on the vehicle-interior side, and a second curved wall, which is curved in a case where the second curved wall is brought into elastic contact with the first sealing member, are connected to each other via a connection part, which is tapered as the connection part extends toward the first sealing member, - an end part of the third inner wall, which end part is located on a connection-part side, being thinner than the other part of the third inner wall, - at least a tip of the connection part being located on a vehicle-interior side of a surface of the third inner wall which surface is located on the vehicle-interior side, and - the first curved wall and the second curved wall being brought into contact with each other in a case where the first end part and the second end part are caused to abut each other, - the end part of the third inner wall, which end part is located on the connection-part side, being gradually decreased in thickness toward the tip of the connection part, - the end part, located on the connection-part side, of the third inner wall having a vehicle-exterior-side side surface that is curved so as to protrude to a vehicle-exterior side, and - the second curved wall being curved so as to, on a rear side, protrude to the vehicle-exterior side and so as to, on a front side, be depressed to the vehicle-exterior side.