The present invention provides a temporary-bonding adhesive having excellent heat resistance, whereby a semiconductor circuit formation substrate and a support substrate can be bonded by a single type of adhesive layer, the adhesive force thereof does not change over the course of steps for manufacturing a semiconductor device or the like, and the adhesive can subsequently be easily de-bonded at room temperature under mild conditions; and a method for manufacturing a semiconductor device using the temporary-bonding adhesive. The present invention includes a temporary-bonding adhesive wherein a polyimide copolymer having at least an acid dianhydride residue and a diamine residue, the diamine residue including both of (A1) a polysiloxane-based diamine residue represented by a general formula (1) in which n is a natural number from 1 to 15, and (B1) a polysiloxane-based diamine residue represented by a general formula (1) in which n is a natural number from 16 to 100, the polyimide copolymer containing 40-99.99 mol % of the (A1) residue and 0.01-60 mol % of the (B1) residue.