An object of the present invention is to provide a bismaleimide (D-BMI) modified product in which an amino group of dimer diamine (DDA) is maleimidized, which has the good heat resistance, and has the sufficiently enhanced processability, and a method for producing the same. There are provided: A bismaleimide (D-BMI) modified product in which an amino group of dimer diamine is maleimidized, the bismaleimide modified product having the following characteristics: 1) An acid value of the D-BMI modified product is 2 mg-KOH/g or less. 2) In 1H-NMR, when quantitative comparison is performed using an integrated value (A) of a peak corresponding to a proton of a methylene group directly bound to a nitrogen atom of a maleimide group and an integrated value (B) of a peak corresponding to a vinyl proton of a maleimide group, A/B is 1.25 or more and 2.00 or less. A method for producing D-BMI, the method including the following steps: 1) A step of preparing a crude D-BMI solution having an acid value of more than 2 mg-KOH/g. 2) A step of lowering an acid value of D-BMI to 2 mg-KOH/g or less by reacting an acid component in the solution with a carbodiimide compound. 3) A step of reacting the solution without a catalyst at 110 to 200° C. in a solvent.