An automatic analyzer configured to perform a qualitative/quantitative analysis of a biological sample, comprising: a storage mechanism configured to store approximate expressions for a change in a measured value with time, each of the approximate expressions being associated with a corresponding test item or specimen; a parameter optimizing mechanism configured to optimize a parameter of the approximate expressions stored in the storage mechanism so as to be associated with an actually measured value; and a determining mechanism configured to determine presence of an abnormality of analysis conditions based on the parameter optimized by the parameter optimizing mechanism; characterized in that one of the approximate expressions is: x = a 0 + ∑ ai * exp − ki * t, where t denotes a measurement point in time, x denotes a calculated value, ∑{} denotes a symbol representing a sum of all values, each value being obtained by substituting i in {} for a value of 1 to n, n denotes a whole number greater than 1, and * denotes a symbol representing multiplication; values of parameters a0, ai and ki in the above approximate expression are calculated so that a difference between an actually measured value at a measurement point in time and a calculated value obtained with the above approximate expression is minimal; wherein the determining mechanism is adapted to determine the presence of the abnormality of analysis conditions based on the parameter values, and wherein the determining mechanism is adapted to determine the presence of the abnormality of analysis conditions by comparing a parameter optimized by the parameter optimizing mechanism with both a distribution of parameter values obtained under normal conditions and a distribution of parameter values obtained under abnormal conditions. a storage mechanism configured to store approximate expressions for a change in a measured value with time, each of the approximate expressions being associated with a corresponding test item or specimen; a parameter optimizing mechanism configured to optimize a parameter of the approximate expressions stored in the storage mechanism so as to be associated with an actually measured value; and a determining mechanism configured to determine presence of an abnormality of analysis conditions based on the parameter optimized by the parameter optimizing mechanism; characterized in that one of the approximate expressions is: x = a 0 + ∑ ai * exp − ki * t, where t denotes a measurement point in time, x denotes a calculated value, ∑{} denotes a symbol representing a sum of all values, each value being obtained by substituting i in {} for a value of 1 to n, n denotes a whole number greater than 1, and * denotes a symbol representing multiplication; values of parameters a0, ai and ki in the above approximate expression are calculated so that a difference between an actually measured value at a measurement point in time and a calculated value obtained with the above approximate expression is minimal; wherein the determining mechanism is adapted to determine the presence of the abnormality of analysis conditions based on the parameter values, and wherein the determining mechanism is adapted to determine the presence of the abnormality of analysis conditions by comparing a parameter optimized by the parameter optimizing mechanism with both a distribution of parameter values obtained under normal conditions and a distribution of parameter values obtained under abnormal conditions. where t denotes a measurement point in time, x denotes a calculated value, ∑{} denotes a symbol representing a sum of all values, each value being obtained by substituting i in {} for a value of 1 to n, n denotes a whole number greater than 1, and * denotes a symbol representing multiplication; values of parameters a0, ai and ki in the above approximate expression are calculated so that a difference between an actually measured value at a measurement point in time and a calculated value obtained with the above approximate expression is minimal; wherein the determining mechanism is adapted to determine the presence of the abnormality of analysis conditions based on the parameter values, and wherein the determining mechanism is adapted to determine the presence of the abnormality of analysis conditions by comparing a parameter optimized by the parameter optimizing mechanism with both a distribution of parameter values obtained under normal conditions and a distribution of parameter values obtained under abnormal conditions.