A detoxifying device (100, 300) having an inner wall (104, 304) that forms a flow passage (103, 303) through which treatment gas flows, the detoxifying device (100, 300) comprising: a first piping (130, 330) that forms a part of the flow passage (103, 303); a replaceable piping section (170, 370) that forms a part of the flow passage (103, 303) at a position downstream of the first piping (130, 330), and is connected to the first piping (130, 330), the replaceable piping section (170, 370) having a first stage sprinkling portion (174, 374) configured to sprinkle a cleaning water to remove a solid product adhering to the inner wall (104, 304); a second piping (150, 350) that forms a part of the flow passage (103, 303) at a position downstream of the replaceable piping section (170, 370), and is connected to the replaceable piping section (170, 370); a second stage sprinkling portion positioned upstream of the first stage sprinkling portion (174, 374) and configured to sprinkle the cleaning water to remove the solid product adhering to the inner wall (104, 304) upstream of the first stage sprinkling portion (174, 374); a pressure sensor configured to measure a pressure in the flow passage (103, 303) upstream of the first stage sprinkling portion (174, 374), and a controller wherein: the controller is configured to control each timing of sprinkling the cleaning water from the first stage sprinkling portion (174, 374) and the second stage sprinkling portion, such that the first stage sprinkling portion (174, 374) sprinkles the cleaning water when the pressure sensor detects a pressure higher than a predetermined threshold value; and the second stage sprinkling portion sprinkles the cleaning water when the treatment gas that causes generation of the solid product stops flowing through the flow passage (103, 303). a first piping (130, 330) that forms a part of the flow passage (103, 303); a replaceable piping section (170, 370) that forms a part of the flow passage (103, 303) at a position downstream of the first piping (130, 330), and is connected to the first piping (130, 330), the replaceable piping section (170, 370) having a first stage sprinkling portion (174, 374) configured to sprinkle a cleaning water to remove a solid product adhering to the inner wall (104, 304); a second piping (150, 350) that forms a part of the flow passage (103, 303) at a position downstream of the replaceable piping section (170, 370), and is connected to the replaceable piping section (170, 370); a second stage sprinkling portion positioned upstream of the first stage sprinkling portion (174, 374) and configured to sprinkle the cleaning water to remove the solid product adhering to the inner wall (104, 304) upstream of the first stage sprinkling portion (174, 374); a pressure sensor configured to measure a pressure in the flow passage (103, 303) upstream of the first stage sprinkling portion (174, 374), and a controller wherein: the controller is configured to control each timing of sprinkling the cleaning water from the first stage sprinkling portion (174, 374) and the second stage sprinkling portion, such that the first stage sprinkling portion (174, 374) sprinkles the cleaning water when the pressure sensor detects a pressure higher than a predetermined threshold value; and the second stage sprinkling portion sprinkles the cleaning water when the treatment gas that causes generation of the solid product stops flowing through the flow passage (103, 303).