A paint film-protecting sheet (1) is provided which effectively prevents adhesive transfer to the paint film. The paint film-protecting sheet (1) has a pressure-sensitive adhesive layer which is comprised of a non-crosslinking pressure-sensitive adhesive (20) adjacent a polyolefin-based resin film serving as a supporting substrate (10). At least a surface portion (12) of the supporting substrate that adjoins the pressure-sensitive adhesive layer satisfies the following conditions: (1) it has an indentation modulus at 25° C. (Er(25)) of from 200 MPa to 1,100 MPa and (2) it has an indentation modulus at −5° C. (Er(−5)) of from 400 MPa to 2,400 MPa.