An automatic analyzer comprising: an analyzing unit which is configured to perform analysis on a liquid sample; an operating unit which is configured to receive information on the analysis and to display the information on the analysis and an analytic result of the analysis using a display device; and a control unit which is configured to control the analyzing unit and the operating unit, characterized in that any of a calibration sample dedicated disk, a position-free disk or a patient specimen dedicated disk can be placed in the analyzing unit as a sample placement disk, wherein the analyzing unit has a disk identifying unit which is configured to identify a type of the sample placement disk, and the control unit is configured to: a. identify the type of the sample placement disk based on an identification result of the disk identifying unit, b. display an analysis start screen based on the identified type of the sample placement disk; and c. perform the analysis on the liquid sample based on the identified type of the sample placement disk, wherein the control unit is configured to display a sample placement condition setting screen for setting: a. an analysis mode name for each of a plurality of analysis modes; b. a sample-type-dependent placement availability and a placeable position range as information on a placeable position to the position-free disk for each type of the liquid sample placed on the position-free disk; and for storing the information on the placeable position to the position-free disk based on information input based on the sample placement condition setting screen from the operating unit, wherein the display analysis start screen displayed in the case where the position-free disk is identified as the sample placement disk includes an analysis-mode combo box for selecting one of said analysis modes and performs the analysis on the liquid sample based on the information on the placeable position to the position-free disk stored for the selected analysis mode, whereas the analysis is performed and completed without displaying the analysis-mode combo box in the case where the calibration sample dedicated disk or the patient specimen dedicated disk is identified as the sample placement disk. an analyzing unit which is configured to perform analysis on a liquid sample; an operating unit which is configured to receive information on the analysis and to display the information on the analysis and an analytic result of the analysis using a display device; and a control unit which is configured to control the analyzing unit and the operating unit, characterized in that any of a calibration sample dedicated disk, a position-free disk or a patient specimen dedicated disk can be placed in the analyzing unit as a sample placement disk, wherein the analyzing unit has a disk identifying unit which is configured to identify a type of the sample placement disk, and the control unit is configured to: a. identify the type of the sample placement disk based on an identification result of the disk identifying unit, b. display an analysis start screen based on the identified type of the sample placement disk; and c. perform the analysis on the liquid sample based on the identified type of the sample placement disk, wherein the control unit is configured to display a sample placement condition setting screen for setting: a. an analysis mode name for each of a plurality of analysis modes; b. a sample-type-dependent placement availability and a placeable position range as information on a placeable position to the position-free disk for each type of the liquid sample placed on the position-free disk; a. identify the type of the sample placement disk based on an identification result of the disk identifying unit, b. display an analysis start screen based on the identified type of the sample placement disk; and c. perform the analysis on the liquid sample based on the identified type of the sample placement disk, a. an analysis mode name for each of a plurality of analysis modes; b. a sample-type-dependent placement availability and a placeable position range as information on a placeable position to the position-free disk for each type of the liquid sample placed on the position-free disk; and for storing the information on the placeable position to the position-free disk based on information input based on the sample placement condition setting screen from the operating unit, wherein the display analysis start screen displayed in the case where the position-free disk is identified as the sample placement disk includes an analysis-mode combo box for selecting one of said analysis modes and performs the analysis on the liquid sample based on the information on the placeable position to the position-free disk stored for the selected analysis mode, whereas the analysis is performed and completed without displaying the analysis-mode combo box in the case where the calibration sample dedicated disk or the patient specimen dedicated disk is identified as the sample placement disk.