A bottom surface part of a bucket includes first and second curved surface parts. The second curved surface part is positioned closer to a back surface part than the first curved surface part. A second curvature radius of the second curved surface part is shorter than a first curvature radius of the first curved surface part. The center of the first curvature radius is positioned to the outside of a main bucket body when viewed from the side. In a horizontal state, the first curved surface part is arranged along or above a reference curved surface when viewed from the side. A connecting part between the first curved surface part and the second curved surface part is positioned more towards a lip part than the portion of the bottom surface part that is positioned lowest in the bottom surface part in the horizontal state when viewed from the side.