An open-close portion structure of a vehicle body includes: an open-close member which opens and closes an opening of the vehicle body; a first hinge member provided on the vehicle body; a second hinge member provided on the open-close member, being pivoted with the first hinge member; and a stretchable stay provided between the vehicle body and the open-close member and biasing the open-close member to open, wherein an end of the stretchable stay is coupled to the second hinge member.