1. A method for checking a blood condition, the method comprising: supplying blood to a centrifugal container of a disk; centrifuging the blood in the centrifugal container to separate plasma from blood cells by rotating the disk; detecting an actual moving distance of the blood cells in the centrifugal container every hour; calculating a first curve representing the actual moving distance of the blood cells in the centrifugal container every hour; calculating a second curve representing a theoretical moving distance of the blood cells every hour; and calculating hematocrit of the blood and viscosity of the plasma by comparing the first curve and the second curve, wherein: the calculating of the second curve is performed by using the following equation, π 6 ⁢ p p ⁢ d p 3 ⁢ r p ″ = π 6 ⁢ ( p p - p f ) ⁢ d p 3 ⁢ w 2 ⁢ r p - 3 ⁢ π ⁢ ⁢ d p ⁢ r p ′ ⁢ { u f ⁡ ( 1 + θ 1 / 3 ) ⁢ exp ⁡ [ 5 ⁢ θ 3 ⁢ ( 1 - θ ) ] } , in the equation, r″ p , r′ p , and r p are calculated by applying predetermined theoretical values to π, p p , d p , p f , w, u f , and θ, π is a circle constant, p p is a density of the blood, d p is a diameter of a blood cell, r″ p is a moving acceleration of the blood cell, p f is a density of the plasma, w is an angular velocity of the disk, r p is a moving distance of the blood cell, r′ p is a moving speed of the blood cell, u f is the viscosity of the plasma, and θ is a volume ratio of the blood cells to an entire volume of the blood, the calculating of the hematocrit of the blood is performed by calculating θ in the equation after applying r p as the actual moving distance of the blood cells every hour of the first curve, and the calculating of the viscosity of the plasma is performed by calculating u f in the equation after applying r p as the actual moving distance of the blood cells ever hour of the first curve.