An image reading device comprising: a light source; a white reference board that is used for shading correction; a reading unit configured to read an original while the original moves on an original platen; a detecting unit (32, 91) configured to detect whether an original is set on the original platen; an acquiring unit configured to cause the light source to move up to a position of the white reference board and to acquire first shading correction data by reading the white reference board, at least when the detecting unit detects setting of the original on the original platen; characterized by: a determining unit configured to determine, upon receiving an original reading start request from an application, whether to execute acquisition of the shading correction data again by using the acquiring unit to acquire second shading correction data, before reading a first original; and a shading correcting unit configured to carry out, upon the determining unit determining to execute acquisition of the shading correction data again by using the acquiring unit before reading the first original, the shading correction by using the second shading correction data, and carries out, upon determining not to execute acquisition of the shading correction data again by using the acquiring unit before reading the first original, the shading correction by using the first shading correction data, wherein the determining unit determines whether to execute acquisition of the shading correction data, based on a type of an application selected from, a fax application, a copy application and a scanner application, that has requested reading of the original by using the reading unit. a light source; a white reference board that is used for shading correction; a reading unit configured to read an original while the original moves on an original platen; a detecting unit (32, 91) configured to detect whether an original is set on the original platen; an acquiring unit configured to cause the light source to move up to a position of the white reference board and to acquire first shading correction data by reading the white reference board, at least when the detecting unit detects setting of the original on the original platen; characterized by: a determining unit configured to determine, upon receiving an original reading start request from an application, whether to execute acquisition of the shading correction data again by using the acquiring unit to acquire second shading correction data, before reading a first original; and a shading correcting unit configured to carry out, upon the determining unit determining to execute acquisition of the shading correction data again by using the acquiring unit before reading the first original, the shading correction by using the second shading correction data, and carries out, upon determining not to execute acquisition of the shading correction data again by using the acquiring unit before reading the first original, the shading correction by using the first shading correction data, wherein the determining unit determines whether to execute acquisition of the shading correction data, based on a type of an application selected from, a fax application, a copy application and a scanner application, that has requested reading of the original by using the reading unit. a determining unit configured to determine, upon receiving an original reading start request from an application, whether to execute acquisition of the shading correction data again by using the acquiring unit to acquire second shading correction data, before reading a first original; and a shading correcting unit configured to carry out, upon the determining unit determining to execute acquisition of the shading correction data again by using the acquiring unit before reading the first original, the shading correction by using the second shading correction data, and carries out, upon determining not to execute acquisition of the shading correction data again by using the acquiring unit before reading the first original, the shading correction by using the first shading correction data, wherein the determining unit determines whether to execute acquisition of the shading correction data, based on a type of an application selected from, a fax application, a copy application and a scanner application, that has requested reading of the original by using the reading unit.