A container for retort food, the container comprising: a container body ; and an inner cap ; wherein the container body comprises a container bowl part having a space which is recessed with a first depth in a downward direction and open in an upward direction and a container flange part constituting a periphery of an upper end of the container bowl part ; wherein the inner cap comprises a cap tray part having a space which is recessed with a second depth in the downward direction and open in the upward direction and a cap flange part constituting a periphery of an upper end of the cap tray part , wherein, when the inner cap is placed on the container body , the cap tray part is located inside an upper region of an inner space of the container bowl part of the container body , and the cap tray part divides the inner space of the container bowl part into upper and lower spaces, wherein, when thermal fusion is performed in a state in which the cap flange part is placed on the container flange part , the lower space inside the container bowl part is sealed, wherein the cap tray part has a three-dimensional rib structure on a bottom surface thereof; characterized in that the three-dimensional rib structure comprises: a first rib which is made of protrusions and recesses repeatedly formed along a circumferential region on the bottom surface of the cap tray part ; and a second rib which is formed on the bottom surface of the cap tray part and has a ring shape having a predetermined inner diameter and of which a cross-section has a shape having predetermined curvature. a container body ; and an inner cap ; wherein the container body comprises a container bowl part having a space which is recessed with a first depth in a downward direction and open in an upward direction and a container flange part constituting a periphery of an upper end of the container bowl part ; wherein the inner cap comprises a cap tray part having a space which is recessed with a second depth in the downward direction and open in the upward direction and a cap flange part constituting a periphery of an upper end of the cap tray part , wherein, when the inner cap is placed on the container body , the cap tray part is located inside an upper region of an inner space of the container bowl part of the container body , and the cap tray part divides the inner space of the container bowl part into upper and lower spaces, wherein, when thermal fusion is performed in a state in which the cap flange part is placed on the container flange part , the lower space inside the container bowl part is sealed, wherein the cap tray part has a three-dimensional rib structure on a bottom surface thereof; characterized in that the three-dimensional rib structure comprises: a first rib which is made of protrusions and recesses repeatedly formed along a circumferential region on the bottom surface of the cap tray part ; and a second rib which is formed on the bottom surface of the cap tray part and has a ring shape having a predetermined inner diameter and of which a cross-section has a shape having predetermined curvature. a first rib which is made of protrusions and recesses repeatedly formed along a circumferential region on the bottom surface of the cap tray part ; and a second rib which is formed on the bottom surface of the cap tray part and has a ring shape having a predetermined inner diameter and of which a cross-section has a shape having predetermined curvature. <EOS>