A surface detection apparatus of a blast furnace burden, the surface detection apparatus which is configured to transmit a detection wave to a surface of a burden such as iron ore and coke that are charged into a blast furnace, and to receive a reflection wave of the detection wave, thereby detecting a surface profile of the burden, characterized by comprising: a guide portion which is cylindrical, and which has an opening portion that is formed by removing a part of a peripheral wall of one end of the guide portion; a reflection plate which is disposed directly above the opening portion; an antenna which is disposed at another end of the guide portion while being opposed to the reflection plate; guide portion rotating means which is configured to rotate the guide portion through a predetermined angle about an axis of the guide portion; guide portion moving means which is configured to move the guide portion to an inside or outside of the blast furnace; and reflection plate tilting means which is configured to tilt the reflection plate at a predetermined angle to an antenna side or an anti-antenna side, wherein the guide portion is inserted through an opening of the blast furnace while disposing the opening portion on a side of the blast furnace, during measurement, after the guide portion is moved to a side of the blast furnace to protrude the opening portion into the furnace, the detection wave is sent from the antenna to the reflection plate, and the guide portion rotating means and the reflection plate tilting means are driven to cause the surface of the burden to be scanned planarly or linearly by the detection wave, and, during non-measurement, the guide portion is moved toward the outside of the blast furnace to retract the opening portion toward the furnace outside, or the guide portion is rotated to direct a peripheral wall other than the opening portion to the surface of the burden. a guide portion which is cylindrical, and which has an opening portion that is formed by removing a part of a peripheral wall of one end of the guide portion; a reflection plate which is disposed directly above the opening portion; an antenna which is disposed at another end of the guide portion while being opposed to the reflection plate; guide portion rotating means which is configured to rotate the guide portion through a predetermined angle about an axis of the guide portion; guide portion moving means which is configured to move the guide portion to an inside or outside of the blast furnace; and reflection plate tilting means which is configured to tilt the reflection plate at a predetermined angle to an antenna side or an anti-antenna side, wherein the guide portion is inserted through an opening of the blast furnace while disposing the opening portion on a side of the blast furnace, during measurement, after the guide portion is moved to a side of the blast furnace to protrude the opening portion into the furnace, the detection wave is sent from the antenna to the reflection plate, and the guide portion rotating means and the reflection plate tilting means are driven to cause the surface of the burden to be scanned planarly or linearly by the detection wave, and, during non-measurement, the guide portion is moved toward the outside of the blast furnace to retract the opening portion toward the furnace outside, or the guide portion is rotated to direct a peripheral wall other than the opening portion to the surface of the burden.