This cab support structure includes a mount device provided on a vehicle body frame; and a connecting mechanism that connects a cab provided above the vehicle body frame via the mount device to the vehicle body frame to be rotatable between a seated position and a tilt position, wherein the connecting mechanism includes a connecting shaft that is connected to the mount device and extends in a horizontal direction, a displacement allowing member connected to the vehicle body frame, and an interlocking member that is connected to the cab and is rotatable in interlock with rotation of the cab, wherein the displacement allowing member has a displacement allowing hole that allows displacement of the connecting shaft in a vertical direction and allows rotation of the connecting shaft between the seated position and the tilt position, and wherein the interlocking member has a displacement allowing portion that allows displacement of the connecting shaft in the vertical direction at the seated position, and a displacement restricting portion that restricts downward displacement of the connecting shaft at the tilt position.