[Object] To provide a mixing apparatus which can reliably prevent an auxiliary liquid from being unintentionally mixed into a main unit even when a failure occurs in a switching device, and which can prevent the switching device or an auxiliary flow route from being damaged even when a pressurizing device malfunctions due to the failure. [Solution] The mixing apparatus includes a pipe L20 circulating dilution water a pipe L17 circulating a disinfecting solution a pressurizing pump 15 circulating the disinfecting solution in the pipe L17 toward the pipe L20 and a check valve 16 capable of optionally turning on and off the pipe L17. The mixing apparatus further includes a discharge flow route L18 which consists of a flow route branched from between the check valve 16 and the pressurizing pump 15 in the pipe L17, and which can discharge the dilution water or the disinfecting solution and an electromagnetic valve 17 which can control the flow route between the check valve 16 and the pressurizing pump 15 in the pipe L17 to have a pressure lower than that of the pipe L20 when not mixing the disinfecting solution with the dilution water.
