To provide a multicolor image forming apparatus in which a plurality of color toner images are transferred in piles onto a transfer material and heat-fixed together under pressure with good releasability, and which ensures good thin line reproducibility.

In the multicolor image forming apparatus of quadruple tandem type, four color toners are combined, wherein only a yellow toner contains 7 parts by mass of a release agent (wax) having a melting point of ≤100°C and has a particle diameter of 10 μm and the other color toners contain 2 parts by mass of the release agent and have a particle diameter of 7μm. A developing unit loaded with the yellow toner is disposed on the most downstream side of a paper conveyance direction. When printing is carried out, a total coverage of four color printings is calculated in a controller 75 of an electrical equipment section 74, and independent dots of the yellow toner are added to regions having a coverage of printings of ≥150% and a coverage of yellow printing of ≤5% so as to achieve a coverage of yellow printing of 5% .