PURPOSE: To decrease an operator's burden and to improve working efficiency as well as to prevent the generation of defective articles at the time of adhesively bonding a reinforcing material to an approximately plane member having a grade.

CONSTITUTION: An adhesive 2 is applied to the base 1a of a bath tub 1 consisting of an FRP molding which is a member to be reinforced and the reinforcing material 3 is imposed thereon. Plural pieces of compression coil springs 5 are disposed apart spaced intervals from each other atop the reinforcing material 3; thereafter, a cylinder 7 is actuated to pressurize the compression coil springs by a pressurizing plate 6.