An analyzer (1; 201) that includes a cleaning system, the analyzer (1; 201) comprising: a cleanser tank (323; 323c) that contains a cleanser (Ls); a cleaning-water tank that contains cleaning water (Lw); a first pipe being connected to the cleanser tank (323; 323c); a second pipe being connected to the first pipe and being adapted to supply the cleanser (Ls) to the analyzer (1; 201); a connection pipe that is connected to the cleaning-water tank and that is bifurcated from the first pipe, so that the cleanser (Ls) is able to flow from the cleanser tank (323; 323c) to the cleaning-water tank; a first pump that is provided to the first pipe and is adapted to pump the cleanser (Ls) out of the cleanser tank (323; 323c) to the cleaning-water tank and the analyzer (1; 201); a valve that is provided to the connection pipe and is adapted to adjust a flow of the cleanser (Ls) from the cleanser tank (323; 323c) into the cleaning-water tank; cleaning-water flow-path constituents (295, 234, 294, 291, 342, 349, 350, 351a, 351b) forming a flow-path through which the cleaning water (Lw) flows from the cleaning-water tank in a process of analyzing a specimen, wherein a third pipe (342, 349) of the cleaning-water flow-path constituents (295, 234, 294, 291, 342, 349, 350, 351a, 351b) connects the cleaning-water tank and the analyzer (1; 201); a second pump that is provided to the third pipe of the cleaning-water flow-path constituents (295, 234, 294, 291, 342, 349, 350, 351a, 351b); and a control unit (4; 240) that is adapted: - to open the valve; - to cause the first pump to pump the cleanser (Ls) out of the cleanser tank (323; 323c) to the cleaning-water tank via the first pipe and the connection pipe to clean the inside of the cleaning-water tank and to the analyzer (1; 201); and - to activate the second pump to pump the cleanser (Ls) from the cleaning-water tank to insides of the cleaning-water flow-path constituents (295, 234, 294, 291, 342, 349, 350, 351a, 351b) to clean the insides of the cleaning-water flow-path constituents (295, 234, 294, 291, 342, 349, 350, 351a, 351b). a cleanser tank (323; 323c) that contains a cleanser (Ls); a cleaning-water tank that contains cleaning water (Lw); a first pipe being connected to the cleanser tank (323; 323c); a second pipe being connected to the first pipe and being adapted to supply the cleanser (Ls) to the analyzer (1; 201); a connection pipe that is connected to the cleaning-water tank and that is bifurcated from the first pipe, so that the cleanser (Ls) is able to flow from the cleanser tank (323; 323c) to the cleaning-water tank; a first pump that is provided to the first pipe and is adapted to pump the cleanser (Ls) out of the cleanser tank (323; 323c) to the cleaning-water tank and the analyzer (1; 201); a valve that is provided to the connection pipe and is adapted to adjust a flow of the cleanser (Ls) from the cleanser tank (323; 323c) into the cleaning-water tank; cleaning-water flow-path constituents (295, 234, 294, 291, 342, 349, 350, 351a, 351b) forming a flow-path through which the cleaning water (Lw) flows from the cleaning-water tank in a process of analyzing a specimen, wherein a third pipe (342, 349) of the cleaning-water flow-path constituents (295, 234, 294, 291, 342, 349, 350, 351a, 351b) connects the cleaning-water tank and the analyzer (1; 201); a second pump that is provided to the third pipe of the cleaning-water flow-path constituents (295, 234, 294, 291, 342, 349, 350, 351a, 351b); and a control unit (4; 240) that is adapted: - to open the valve; - to cause the first pump to pump the cleanser (Ls) out of the cleanser tank (323; 323c) to the cleaning-water tank via the first pipe and the connection pipe to clean the inside of the cleaning-water tank and to the analyzer (1; 201); and - to activate the second pump to pump the cleanser (Ls) from the cleaning-water tank to insides of the cleaning-water flow-path constituents (295, 234, 294, 291, 342, 349, 350, 351a, 351b) to clean the insides of the cleaning-water flow-path constituents (295, 234, 294, 291, 342, 349, 350, 351a, 351b). - to open the valve; - to cause the first pump to pump the cleanser (Ls) out of the cleanser tank (323; 323c) to the cleaning-water tank via the first pipe and the connection pipe to clean the inside of the cleaning-water tank and to the analyzer (1; 201); and - to activate the second pump to pump the cleanser (Ls) from the cleaning-water tank to insides of the cleaning-water flow-path constituents (295, 234, 294, 291, 342, 349, 350, 351a, 351b) to clean the insides of the cleaning-water flow-path constituents (295, 234, 294, 291, 342, 349, 350, 351a, 351b).