A temporary fixing composition is provided that is used to temporarily fix a first bonding target material and a second bonding target material to each other before the two bonding target materials are bonded to each other. The temporary fixing composition contains a first organic component having a viscosity of less than 70 mPa·s at 25° C. and a boiling point of 200° C. or lower and a second organic component having a viscosity of 70 mPa·s or greater at 25° C. and a boiling point of 210° C. or higher. It is preferable that, when thermogravimetry-differential thermal analysis is performed under the conditions at a temperature increase rate of 10° C./min in a nitrogen atmosphere with a sample mass of 30 mg, the 95% mass reduction temperature is lower than 300° C.