A combine harvester comprising: a reaping device configured to cut grain culms that are in an agricultural field; a harvest frame configured to receive the grain culms cut by the reaping device; a rake-in auger that is disposed within the harvest frame to be rotatable about a rotary axis extending in a right/left direction of a harvester body, the rake-in auger being configured to convey the grain culms inside the harvest frame in the right/left direction of the harvester body to rake in the grain culms toward a rear of the harvester body; and a feeder that is communicatively connected to a rear wall of the harvest frame for conveying the grain culms raked in by the rake-in auger toward the rear of the harvester body, and a grain culm sensor that is disposed at a grain culm feed port in the feeder for detecting a presence of the grain culms when the grain culms come into contact with the grain culm sensor, wherein the feeder includes a pair of front and rear rotating members (19, 20) rotatable about the rotary axis (X2, X3) extending in the right/left direction of the harvesting body, a pair of right and left conveyor chains that are wound around the pair of front and rear rotating members (19, 20), and a plurality of conveyor guides that extend between the pair of right and left conveyor chains to engage the grain culms, the feeder being configured to convey the grain culms rearward relative to the harvester body along a lower path of the conveyor chains, characterized in that: the grain culm sensor includes a claw-shaped detection member configured to swing when the conveyed grain culms come into contact with the grain culm sensor, to detect the presence of the grain culms, and the detection member is configured to swing along a bottom plate of the feeder, the detection member is disposed at a position between the rotary axis of the front rotating member and a bottom edge of the conveyor guide positioned on the lower path, in a height direction of the grain culm feed port. a reaping device configured to cut grain culms that are in an agricultural field; a harvest frame configured to receive the grain culms cut by the reaping device; a rake-in auger that is disposed within the harvest frame to be rotatable about a rotary axis extending in a right/left direction of a harvester body, the rake-in auger being configured to convey the grain culms inside the harvest frame in the right/left direction of the harvester body to rake in the grain culms toward a rear of the harvester body; and a feeder that is communicatively connected to a rear wall of the harvest frame for conveying the grain culms raked in by the rake-in auger toward the rear of the harvester body, and a grain culm sensor that is disposed at a grain culm feed port in the feeder for detecting a presence of the grain culms when the grain culms come into contact with the grain culm sensor, wherein the feeder includes a pair of front and rear rotating members (19, 20) rotatable about the rotary axis (X2, X3) extending in the right/left direction of the harvesting body, a pair of right and left conveyor chains that are wound around the pair of front and rear rotating members (19, 20), and a plurality of conveyor guides that extend between the pair of right and left conveyor chains to engage the grain culms, the feeder being configured to convey the grain culms rearward relative to the harvester body along a lower path of the conveyor chains, characterized in that: the grain culm sensor includes a claw-shaped detection member configured to swing when the conveyed grain culms come into contact with the grain culm sensor, to detect the presence of the grain culms, and the detection member is configured to swing along a bottom plate of the feeder, the detection member is disposed at a position between the rotary axis of the front rotating member and a bottom edge of the conveyor guide positioned on the lower path, in a height direction of the grain culm feed port. the grain culm sensor includes a claw-shaped detection member configured to swing when the conveyed grain culms come into contact with the grain culm sensor, to detect the presence of the grain culms, and the detection member is configured to swing along a bottom plate of the feeder, the detection member is disposed at a position between the rotary axis of the front rotating member and a bottom edge of the conveyor guide positioned on the lower path, in a height direction of the grain culm feed port.