An image forming apparatus comprising: a forming portion configured to form an image; an adjusting portion configured to execute an adjustment for correcting a pre-selected adjustable image forming condition, said adjustment being executed based on a measurement of an image formed by said forming portion; and a control portion configured to control execution of said adjustment achieved by said adjusting portion, wherein: said control portion obtains a plurality of kinds of variation values (NC, TEMP, RB, MA, RH, RD, TV), which individually indicate a different state variation capable of involving a state change in said pre-selected adjustable image forming condition, characterized in that said control portion is configured to calculate a complex evaluation (Ecr, Eid) of a current state of said pre-selected adjustable image forming condition based on said plurality of kinds of variation values (NC, TEMP, RB, MA, RH, RD, TV), and to determine a starting time for execution of said adjustment based on said complex evaluation (Ecr, Eid); said adjusting portion is configured to execute at least two kinds of adjustment, including an adjustment for correcting an image forming position and an adjustment for correcting an image density; and said control portion is configured to determine a starting time for each of said at least two kinds of adjustment, independently from a starting time for another of said at least two kinds of adjustment, wherein said plurality of kinds of variation values (NC, TEMP, RB, MA, RH, RD, TV) to be used for determination of a starting time for each of said at least two kinds of adjustment differ from those to be used for determination of a starting time for another of said at least two kinds of adjustment. a forming portion configured to form an image; an adjusting portion configured to execute an adjustment for correcting a pre-selected adjustable image forming condition, said adjustment being executed based on a measurement of an image formed by said forming portion; and a control portion configured to control execution of said adjustment achieved by said adjusting portion, wherein: said control portion obtains a plurality of kinds of variation values (NC, TEMP, RB, MA, RH, RD, TV), which individually indicate a different state variation capable of involving a state change in said pre-selected adjustable image forming condition, characterized in that said control portion is configured to calculate a complex evaluation (Ecr, Eid) of a current state of said pre-selected adjustable image forming condition based on said plurality of kinds of variation values (NC, TEMP, RB, MA, RH, RD, TV), and to determine a starting time for execution of said adjustment based on said complex evaluation (Ecr, Eid); said adjusting portion is configured to execute at least two kinds of adjustment, including an adjustment for correcting an image forming position and an adjustment for correcting an image density; and said control portion is configured to determine a starting time for each of said at least two kinds of adjustment, independently from a starting time for another of said at least two kinds of adjustment, wherein said plurality of kinds of variation values (NC, TEMP, RB, MA, RH, RD, TV) to be used for determination of a starting time for each of said at least two kinds of adjustment differ from those to be used for determination of a starting time for another of said at least two kinds of adjustment. said control portion obtains a plurality of kinds of variation values (NC, TEMP, RB, MA, RH, RD, TV), which individually indicate a different state variation capable of involving a state change in said pre-selected adjustable image forming condition, said control portion is configured to calculate a complex evaluation (Ecr, Eid) of a current state of said pre-selected adjustable image forming condition based on said plurality of kinds of variation values (NC, TEMP, RB, MA, RH, RD, TV), and to determine a starting time for execution of said adjustment based on said complex evaluation (Ecr, Eid); said adjusting portion is configured to execute at least two kinds of adjustment, including an adjustment for correcting an image forming position and an adjustment for correcting an image density; and said control portion is configured to determine a starting time for each of said at least two kinds of adjustment, independently from a starting time for another of said at least two kinds of adjustment, wherein said plurality of kinds of variation values (NC, TEMP, RB, MA, RH, RD, TV) to be used for determination of a starting time for each of said at least two kinds of adjustment differ from those to be used for determination of a starting time for another of said at least two kinds of adjustment.