An arctic ship with a derrick (2, 110), comprising: the derrick (2, 110) forming an enclosed space blocked from outside air; an air supply/exhaust device (330, 340) installed to communicate an inner space of the derrick (2, 110) with the exterior, characterised in that the arctic ship further comprises: a moonpool (3, 120) coupled to a lower portion of the derrick (2, 110) to communicate with the derrick (2, 110) and blocked from the outside air; and wherein air condition of the inner space is maintained or controlled at a predetermined range by the air supply/exhaust device, wherein the arctic ship has a structure enclosed from the derrick (2, 110) to the moonpool (3, 120), and compensates a negative pressure or a positive pressure generated in the enclosed derrick and the moonpool (3, 120) due to influence of waves transferred to the moonpool (3, 120), and that the arctic ship further comprises: one or more temperature sensors (351, 352, 353) installed in the inside of the derrick (2, 110) to monitor an internal temperature of the derrick; one or more pressure sensors installed in the inside of the moonpool (3, 120) to monitor an internal pressure of the moonpool (3, 120); and a control unit controlling the operations of the supply/exhaust device (330, 340), based on internal temperature and pressure information monitored by the temperature sensors (351, 352, 353) and the pressure sensors. the derrick (2, 110) forming an enclosed space blocked from outside air; an air supply/exhaust device (330, 340) installed to communicate an inner space of the derrick (2, 110) with the exterior, characterised in that the arctic ship further comprises: a moonpool (3, 120) coupled to a lower portion of the derrick (2, 110) to communicate with the derrick (2, 110) and blocked from the outside air; and wherein air condition of the inner space is maintained or controlled at a predetermined range by the air supply/exhaust device, wherein the arctic ship has a structure enclosed from the derrick (2, 110) to the moonpool (3, 120), and compensates a negative pressure or a positive pressure generated in the enclosed derrick and the moonpool (3, 120) due to influence of waves transferred to the moonpool (3, 120), and that the arctic ship further comprises: one or more temperature sensors (351, 352, 353) installed in the inside of the derrick (2, 110) to monitor an internal temperature of the derrick; one or more pressure sensors installed in the inside of the moonpool (3, 120) to monitor an internal pressure of the moonpool (3, 120); and a control unit controlling the operations of the supply/exhaust device (330, 340), based on internal temperature and pressure information monitored by the temperature sensors (351, 352, 353) and the pressure sensors. a moonpool (3, 120) coupled to a lower portion of the derrick (2, 110) to communicate with the derrick (2, 110) and blocked from the outside air; and wherein air condition of the inner space is maintained or controlled at a predetermined range by the air supply/exhaust device, wherein the arctic ship has a structure enclosed from the derrick (2, 110) to the moonpool (3, 120), and compensates a negative pressure or a positive pressure generated in the enclosed derrick and the moonpool (3, 120) due to influence of waves transferred to the moonpool (3, 120), and that the arctic ship further comprises: one or more temperature sensors (351, 352, 353) installed in the inside of the derrick (2, 110) to monitor an internal temperature of the derrick; one or more pressure sensors installed in the inside of the moonpool (3, 120) to monitor an internal pressure of the moonpool (3, 120); and a control unit controlling the operations of the supply/exhaust device (330, 340), based on internal temperature and pressure information monitored by the temperature sensors (351, 352, 353) and the pressure sensors. one or more temperature sensors (351, 352, 353) installed in the inside of the derrick (2, 110) to monitor an internal temperature of the derrick; one or more pressure sensors installed in the inside of the moonpool (3, 120) to monitor an internal pressure of the moonpool (3, 120); and a control unit controlling the operations of the supply/exhaust device (330, 340), based on internal temperature and pressure information monitored by the temperature sensors (351, 352, 353) and the pressure sensors.