To easily make a pattern image small in size and to decrease toner consumption required to detect toner adhesive amount.

A toner image includes: a first pattern 601 formed on an intermediate transfer belt 104; a second pattern 602 successively formed on the upstream side of the first pattern 601 in the conveying direction DF of the intermediate transfer belt, having the same density as the first pattern 601, and formed in such a state that it extends in a direction having a tilt angle to the conveying direction DF of the intermediate transfer belt and a direction DL orthogonal to the conveying direction DF; and a third pattern 603 successively formed on the upstream side of the second pattern 602 in the conveying direction DF of the intermediate transfer belt, having different density from the first pattern 601, and formed so that width D3 in the direction DL orthogonal to the conveying direction DF may be smaller than the width D1 of the first pattern 601.