A blood analysis apparatus comprising at least: plural blood cell counting parts (31, 32, 33, 34); a probe unit with a single sampling nozzle, the single sampling nozzle being connected to a quantitative pump; and a control part which controls operations of the blood cell counting parts (31, 32, 33, 34) and the probe unit with the single sampling nozzle, and performs data processing of blood analysis; wherein the probe unit with the single sampling nozzle is adapted to be controlled by the control part to perform the following steps: to suck a predetermined amount of a blood specimen, which is contained in a specimen container to be set in the blood analysis apparatus; and then to dispense the predetermined amount of blood specimen to each of the blood cell counting parts (31, 32, 33, 34) at a predetermined ratio, wherein each blood cell counting part (31, 32, 33, 34) is adapted to be controlled by the control part, to obtain each count data for each blood cell counting, wherein the control part is adapted to process the count data from each blood cell counting part (31, 32, 33, 34) and to perform blood analysis, and wherein two or more blood cell counting parts (31, 32, 33, 34) are each adapted to obtain the count data about a particular, same kind of blood cell, in addition to the count data that each blood cell counting originally intends to obtain, and wherein the control part is further adapted: to respectively calculate a ratio or number of the existing particular kind of blood cells from the count data about the particular kind of blood cell, said count data obtained by two or more blood cell counting parts (31, 32, 33, 34); and to compare the calculation results to determine whether the calculation results are within a predetermined allowable range, thereby to determine whether the amount of the blood specimen sucked in the sampling nozzle was normal or insufficient. plural blood cell counting parts (31, 32, 33, 34); a probe unit with a single sampling nozzle, the single sampling nozzle being connected to a quantitative pump; and a control part which controls operations of the blood cell counting parts (31, 32, 33, 34) and the probe unit with the single sampling nozzle, and performs data processing of blood analysis; wherein the probe unit with the single sampling nozzle is adapted to be controlled by the control part to perform the following steps: to suck a predetermined amount of a blood specimen, which is contained in a specimen container to be set in the blood analysis apparatus; and then to dispense the predetermined amount of blood specimen to each of the blood cell counting parts (31, 32, 33, 34) at a predetermined ratio, wherein to suck a predetermined amount of a blood specimen, which is contained in a specimen container to be set in the blood analysis apparatus; and then to dispense the predetermined amount of blood specimen to each of the blood cell counting parts (31, 32, 33, 34) at a predetermined ratio, wherein each blood cell counting part (31, 32, 33, 34) is adapted to be controlled by the control part, to obtain each count data for each blood cell counting, wherein the control part is adapted to process the count data from each blood cell counting part (31, 32, 33, 34) and to perform blood analysis, and wherein two or more blood cell counting parts (31, 32, 33, 34) are each adapted to obtain the count data about a particular, same kind of blood cell, in addition to the count data that each blood cell counting originally intends to obtain, and wherein the control part is further adapted: to respectively calculate a ratio or number of the existing particular kind of blood cells from the count data about the particular kind of blood cell, said count data obtained by two or more blood cell counting parts (31, 32, 33, 34); and to compare the calculation results to determine whether the calculation results are within a predetermined allowable range, thereby to respectively calculate a ratio or number of the existing particular kind of blood cells from the count data about the particular kind of blood cell, said count data obtained by two or more blood cell counting parts (31, 32, 33, 34); and to compare the calculation results to determine whether the calculation results are within a predetermined allowable range, thereby to determine whether the amount of the blood specimen sucked in the sampling nozzle was normal or insufficient.