A flushing apparatus according to embodiments of the present disclosure includes: a main body configured to connect a connection pipe for guiding a hazardous medicinal liquid harmful to a human body when exposed to an ambient air and a patient connection module for injecting the hazardous medicinal liquid into a patient, the main body configured to form a first flow path for guiding the hazardous medicinal liquid from the connection pipe to the patient connection module, the main body including a flushing portion forming a second flow path connected to a predetermined connection point located between both ends of the first flow path; and a flow rate reduction part disposed at upstream side of the connection point in the first flow path and configured to reduce a flow rate of the hazardous medicinal liquid flowing through the first flow path. The present disclosure shows various embodiments of the flushing apparatus.