Resin composition

Provided is a resin composition having excellent preservation stability and solubility in a low-boiling point solvent such as methyl ethyl ketone. The resin composition is produced through a melt-mixing step of melt-mixing a resin mixture so that, in 100 parts by mass of the resin mixture containing (B) a benzo-oxazine compound and (A) a polymaleimide compound represented by formula (1), the content of (A) the polymaleimide compound is 30 to 95 parts by mass. (1) (In formula [1]: n1 represents an integer between 0 and 10; each X1 represents, independently, an alkylene group having a number of carbons ranging from 1 to 10, a group represented by formula [2], a group represented by the formula -SO2-, a group represented by -CO-, an oxygen atom, or a single bond; each R1 represents, independently, a hydrocarbon group having a number of carbons ranging from 1 to 6; each "a" represents, independently, an integer between 0 and 4; and each "b" represents, independently, an integer between 0 and 3.) (2) (In formula [