An automatic analysis apparatus , comprising: a dispensing mechanism configured to suck liquid from a first vessel and discharges the liquid to a second vessel , wherein the first vessel is a reagent vessel for containing a reagent, a specimen vessel for containing a specimen or a diluent vessel for containing a diluent and the second vessel is a reaction vessel; an analysis unit configured to analyse the liquid in the second vessel ; a vessel installment unit in which the second vessel is able to be installed; an input unit configured to receive an operation of the dispensing mechanism ; a control unit configured to control the dispensing mechanism in accordance with the operation received by the input unit; and a holding unit configured to hold an uncontained second vessel in which liquid is not contained; an external transport mechanism configured to transport the uncontained vessel from the holding unit to the vessel installment unit ; a display unit ; characterized in that it further comprises an external weight measurement unit ; wherein the external transport mechanism is configured to transport the uncontained second vessel or the contained second vessel disposed in the automatic analysis apparatus to the outside of the automatic analysis apparatus , wherein the control unit is configured to cause the external transport mechanism to transport the uncontained second vessel or the contained second vessel to the external weight measuring unit , the external weight measuring unit to measure a weight of the uncontained second vessel and a weight of the contained second vessel to calculate a discharge amount or a suction amount of the dispensing mechanism , and the display unit to display the calculated discharge amount or the calculated suction amount. a dispensing mechanism configured to suck liquid from a first vessel and discharges the liquid to a second vessel , wherein the first vessel is a reagent vessel for containing a reagent, a specimen vessel for containing a specimen or a diluent vessel for containing a diluent and the second vessel is a reaction vessel; an analysis unit configured to analyse the liquid in the second vessel ; a vessel installment unit in which the second vessel is able to be installed; an input unit configured to receive an operation of the dispensing mechanism ; a control unit configured to control the dispensing mechanism in accordance with the operation received by the input unit; and a holding unit configured to hold an uncontained second vessel in which liquid is not contained; an external transport mechanism configured to transport the uncontained vessel from the holding unit to the vessel installment unit ; a display unit ; characterized in that it further comprises an external weight measurement unit ; wherein the external transport mechanism is configured to transport the uncontained second vessel or the contained second vessel disposed in the automatic analysis apparatus to the outside of the automatic analysis apparatus , wherein the control unit is configured to cause the external transport mechanism to transport the uncontained second vessel or the contained second vessel to the external weight measuring unit , the external weight measuring unit to measure a weight of the uncontained second vessel and a weight of the contained second vessel to calculate a discharge amount or a suction amount of the dispensing mechanism , and the display unit to display the calculated discharge amount or the calculated suction amount. <EOS>