PROBLEM TO BE SOLVED: To provide a method for producing a dyed resin body in which a dyed resin body can be produced by, while suppressing the occurrence of differences in temperature rise ratio of each part of the resin body, heating the resin body by irradiation of electromagnetic wave to fix a dye, and to provide a dyeing apparatus.SOLUTION: A process for producing a dyed resin body is a process for producing a dyed resin body by heating a resin body with a surface onto which a dye is adhered, to fix the dye onto the resin body. The process for producing a dyed resin body comprises an adhesion step (S3) and a fixing step (S7). In the adhesion step (S3), an adhering body having adhesiveness to the resin body is adhered to the resin body to be dyed. In the fixing step (S7), the resin body onto which the adhering body is adhered in the adhesion step, is heated by irradiation of electromagnetic wave from an electromagnetic wave generation unit that generates electromagnetic waves, to fix the dye.
