A spun yarn drawing apparatus comprising: at least one preheating roller (31 - 33) which heats yarns before drawn; at least one conditioning roller (34, 35) which is provided downstream in a yarn running direction of the at least one preheating roller (31 - 33) and is higher in temperature and speed than the at least one preheating roller (31 - 33); and a thermal insulation box which houses the at least one preheating roller (31 - 33) and the at least one conditioning roller (34, 35), the yarns being drawn between the at least one preheating roller (31 - 33) and the at least one conditioning roller (34, 35), the spun yarn drawing apparatus further including: at least one partition portion (43a, 43b) provided between the at least one preheating roller (31 - 33) and the at least one conditioning roller (34, 35); and a communication passage which causes a low-temperature space which is on the preheating roller (31 - 33) side of the at least one partition portion (43a, 43b) to communicate with a high-temperature space which is on the conditioning roller (34, 35) side of the at least one partition portion (43a, 43b); characterized in that at least one shutter (48, 49) is provided to change the flow passage area of the communication passage, and wherein, the communication passage is a passage formed at a location different from a yarn path between the at least one preheating roller (31 - 33) and the at least one conditioning roller (34, 35). at least one preheating roller (31 - 33) which heats yarns before drawn; at least one conditioning roller (34, 35) which is provided downstream in a yarn running direction of the at least one preheating roller (31 - 33) and is higher in temperature and speed than the at least one preheating roller (31 - 33); and a thermal insulation box which houses the at least one preheating roller (31 - 33) and the at least one conditioning roller (34, 35), the yarns being drawn between the at least one preheating roller (31 - 33) and the at least one conditioning roller (34, 35), the spun yarn drawing apparatus further including: at least one partition portion (43a, 43b) provided between the at least one preheating roller (31 - 33) and the at least one conditioning roller (34, 35); and a communication passage which causes a low-temperature space which is on the preheating roller (31 - 33) side of the at least one partition portion (43a, 43b) to communicate with a high-temperature space which is on the conditioning roller (34, 35) side of the at least one partition portion (43a, 43b); characterized in that at least one shutter (48, 49) is provided to change the flow passage area of the communication passage, and wherein, the communication passage is a passage formed at a location different from a yarn path between the at least one preheating roller (31 - 33) and the at least one conditioning roller (34, 35). at least one partition portion (43a, 43b) provided between the at least one preheating roller (31 - 33) and the at least one conditioning roller (34, 35); and a communication passage which causes a low-temperature space which is on the preheating roller (31 - 33) side of the at least one partition portion (43a, 43b) to communicate with a high-temperature space which is on the conditioning roller (34, 35) side of the at least one partition portion (43a, 43b); characterized in that at least one shutter (48, 49) is provided to change the flow passage area of the communication passage, and wherein, the communication passage is a passage formed at a location different from a yarn path between the at least one preheating roller (31 - 33) and the at least one conditioning roller (34, 35).