AUTOMATIC ANALYZER

PURPOSE:To facilitate the detachment and holding a measuring instrument and to perfectly automate the washing of the washing instrument by setting the ring grooves formed on the outer peripheries of the opposed contact parts of a pair of scratching rotary bodies to the washing holes corresponding to the measuring instrument. CONSTITUTION:A washing apparatus 9 washes the used measuring instrument detached by the analytical robot controlled by a computer unit in such a state that said instrument is held by rotary brushes 903a, 903b being a pair of scratching rotary bodies. Both of the rotary brushes 903a, 903b have ring grooves 921, 922 having a triangular cross-section formed to the outer peripheries thereof, and washing hole 924 holding a large rotor 925 and a pH electrode in an inserted state and a washing hole 926 holding a small diameter rotor in an inserted state are formed on the opposed contact surfaces 923 or both brushes. For example, when the used large rotor 925 is washed, the rotor 925 is detached by the analytical robot to be positioned directly above a washing tank 904 and subsequently held to the washing hole 924 to drive a drive motor 927 and the brushes 903a, 903b are rotated to scratch and drop a liquid resin and an automatic water supply and drain system is started.