To provide an apparatus and a method for manufacturing a sheet raw material capable of manufacturing a raw material that can accurately detect a temporarily adhesive region where an adhesive sheet temporarily adheres to a release sheet and a temporarily non-adhesive region where the adhesive sheet does not adhere.

The apparatus 1 for manufacturing the sheet raw material includes: a feed-out unit 2 that feeds out the first raw material R1; a cutting unit 3 that forms a predetermined shaped cut-in C on a belt-shaped sheet S of the first raw material R1 that has been fed out; a collection unit 4 that winds and collects an unnecessary sheet S2 located outside the cut-in C; a release plate 5 that releases a release sheet RL from the adhesive sheet S1 located inside the cut-in C; a bypass unit 6 that bypasses the release sheet RL; a contrast enhancer 7 that forms a mat treatment surface RA on one surface of the release sheet RL; and a temporal re-adhesion unit 8 that makes the adhesive sheet S1 re-adhere to the mat treatment surface RA of the bypassed release sheet RL.