A flush device including: a first housing provided with a first flow path； a second housing provided with a second flow path, the second housing being coupled to the first housing； a flow control device including a protrusion and a through hole connecting the first flow path to the second flow path in fluid communication； and an elastic member provided around the base of the flow control device to seal off a space between the first and the second flow paths. The elastic member is deformed to further connect the first and second flow paths in fluid communication. The first housing has an inner periphery provided with fitting receiving portions each being fitted to each of the fitting projections of the protrusion. According to this structure, the flush device can discharge a chemical liquid at a flow rate close to a defined amount.
