A urine analyzer capable of operating in a urine measurement mode and a body fluid measurement mode, the urine analyzer comprising: a specimen preparing section configured to prepare a measurement specimen; a detecting section configured to derive signals of particles in the measurement specimen supplied from the specimen preparing section; and a computer programmed to, under the urine measurement mode, control the specimen preparing section to prepare a first measurement specimen by mixing a first aliquot of a urine sample and a first reagent, to prepare a second measurement specimen by mixing a second aliquot of the urine sample and a second reagent having a hemolytic effect, and to supply the first and second measurement specimens to the detecting section; and analyze the signals of the first measurement specimen to measure red blood cells in the urine sample and analyze the signals of the second measurement specimen to measure bacteria in the urine sample, under the body fluid measurement mode, control the specimen preparing section to prepare a third measurement specimen by mixing a first aliquot of a sample of body fluid not including urine and the first reagent used in, to prepare a fourth measurement specimen by mixing a second aliquot of said body fluid sample and the second reagent used in, and to supply the third and fourth measurement specimens to the detecting section; and analyze the signals of the third measurement specimen to measure red blood cells in the body fluid sample and analyze the signals of the fourth measurement specimen to measure white blood cells in the body fluid sample. a specimen preparing section configured to prepare a measurement specimen; a detecting section configured to derive signals of particles in the measurement specimen supplied from the specimen preparing section; and a computer programmed to, under the urine measurement mode, control the specimen preparing section to prepare a first measurement specimen by mixing a first aliquot of a urine sample and a first reagent, to prepare a second measurement specimen by mixing a second aliquot of the urine sample and a second reagent having a hemolytic effect, and to supply the first and second measurement specimens to the detecting section; and analyze the signals of the first measurement specimen to measure red blood cells in the urine sample and analyze the signals of the second measurement specimen to measure bacteria in the urine sample, under the body fluid measurement mode, control the specimen preparing section to prepare a third measurement specimen by mixing a first aliquot of a sample of body fluid not including urine and the first reagent used in, to prepare a fourth measurement specimen by mixing a second aliquot of said body fluid sample and the second reagent used in, and to supply the third and fourth measurement specimens to the detecting section; and analyze the signals of the third measurement specimen to measure red blood cells in the body fluid sample and analyze the signals of the fourth measurement specimen to measure white blood cells in the body fluid sample. under the urine measurement mode, control the specimen preparing section to prepare a first measurement specimen by mixing a first aliquot of a urine sample and a first reagent, to prepare a second measurement specimen by mixing a second aliquot of the urine sample and a second reagent having a hemolytic effect, and to supply the first and second measurement specimens to the detecting section; and analyze the signals of the first measurement specimen to measure red blood cells in the urine sample and analyze the signals of the second measurement specimen to measure bacteria in the urine sample, under the body fluid measurement mode, control the specimen preparing section to prepare a third measurement specimen by mixing a first aliquot of a sample of body fluid not including urine and the first reagent used in, to prepare a fourth measurement specimen by mixing a second aliquot of said body fluid sample and the second reagent used in, and to supply the third and fourth measurement specimens to the detecting section; and analyze the signals of the third measurement specimen to measure red blood cells in the body fluid sample and analyze the signals of the fourth measurement specimen to measure white blood cells in the body fluid sample.