An exhaust emission purifying apparatus for an engine, operable to add a reducing agent for NOx to an exhaust gas of the engine thereby reducing the NO x in the exhaust gas, comprising: a tank for storing the reducing agent to be added to the exhaust gas or a precursor thereof, in an aqueous solution state; a detecting unit for detecting a predetermined state parameter on the aqueous solution based on a thermal characteristic of the aqueous solution stored in the tank; and a calculating unit for performing a predetermined calculation on abnormalities of the aqueous solution based on the detected state parameter, wherein the calculating unit includes: an abnormality detecting section adapted to detect a predetermined abnormality on the aqueous solution when the detected state parameter is within an abnormal region other than a predetermined region defined as a normal region; and an abnormality judging section which is adapted to make an abnormality judgment upon an establishment of a predetermined determinate condition after the abnormality is detected, the abnormality detecting section is adapted to detect a first abnormality when the detected state parameter is within a first region in the abnormal region, and the abnormality judging section is adapted to make a first abnormality judgment in association with the first abnormality detection, characterized in that the abnormality detecting section is also adapted to detect a second abnormality when the detected state parameter is within a second region defined as a different region from the first region in the abnormal region, the abnormality judging section is also adapted to make a second abnormality judgment in association with the second abnormality detection, the abnormality judging section being adapted such that after the first abnormality judgment is made, when the second abnormality is detected as a result that the detected state parameter is directly shifted from the first region to the second region, the first abnormality judgment is maintained for a predetermined period of time from the detection of the second abnormality concerned, the abnormality judging section is adapted to perform setting of a counter therein, which is increased by a predetermined value at every time when the second abnormality is detected, and to make the second abnormality judgment based on a value counted by the counter, the abnormality judging section is adapted to perform setting of the counter on conducting of at least the second abnormality judgment, and to make the second abnormality judgment when the counter reaches a predetermined abnormality judgment value, and the predetermined period of time is determined as being a period of time elapsing from a detection of the second abnormality by the detecting unit until the counter reaches the predetermined abnormality judgment value. a tank for storing the reducing agent to be added to the exhaust gas or a precursor thereof, in an aqueous solution state; a detecting unit for detecting a predetermined state parameter on the aqueous solution based on a thermal characteristic of the aqueous solution stored in the tank; and a calculating unit for performing a predetermined calculation on abnormalities of the aqueous solution based on the detected state parameter, wherein the calculating unit includes: an abnormality detecting section adapted to detect a predetermined abnormality on the aqueous solution when the detected state parameter is within an abnormal region other than a predetermined region defined as a normal region; and an abnormality judging section which is adapted to make an abnormality judgment upon an establishment of a predetermined determinate condition after the abnormality is detected, an abnormality detecting section adapted to detect a predetermined abnormality on the aqueous solution when the detected state parameter is within an abnormal region other than a predetermined region defined as a normal region; and an abnormality judging section which is adapted to make an abnormality judgment upon an establishment of a predetermined determinate condition after the abnormality is detected, the abnormality detecting section is adapted to detect a first abnormality when the detected state parameter is within a first region in the abnormal region, and the abnormality judging section is adapted to make a first abnormality judgment in association with the first abnormality detection,