The sheet connection device (1) includes: adhesive rollers (10, 10); a joining unit (20) and a cutting unit (30); and feed rollers (40, 40). The cutting unit (30) is capable of forming a connected end portion (SE2) by cutting the second bonding sheet (S2). The adhesive rollers (10, 10) separate the first bonding sheet (S1) into an adhesive sheet (SA) and a release sheet (SP) to form a separated portion (50) by feeding the first bonding sheet (S1) while holding a connecting end portion (SE1) of the first bonding sheet (S1). The feed rollers (40, 40) inserts the connected end portion (SE2) into the separated portion (50) by feeding the second bonding sheet (S2) toward the connecting end portion (SE1). The joining unit (20) connects the connecting end portion (SE1) and the connected end portion (SE2) to each other by adhesion or welding.

The splicer, for splicing a first web material and a second web material, comprises a retaining device adapted to hold a leading edge of the second web material in a standby position; and a dispenser for an adhesive, comprising a dispensing member configured to dispense a strip of adhesive onto the leading edge of the second web material in the standby position. An unwinder and a line are also disclosed, using splicers as defined above, as well as a method for splicing two web materials together.