METHOD FOR MANUFACTURING WET FRICTION PLATE, WET FRICTION PLATE, AND WET MULTIPLE-PLATE CLUTCH DEVICE HAVING WET FRICTION PLATE

Provided are a method for manufacturing a wet friction plate, whereby efficiency of the work of forming a fine groove on a friction material can be improved, the wet friction plate, and a wet multiple-plate clutch device having the wet friction plate. In the method for manufacturing a wet friction plate 200, a core metal 201 and a friction material 210 are prepared in a first step. Thereafter, a resin layer 203 is formed on the core metal 201 in a second step. The resin layer 203 is formed on each of entire two plate surfaces of the core metal 201. Subsequently, the friction material 210 is attached onto the resin layer 203 of the core metal 201 in a third step. Subsequently, a fine groove 211 is formed in the friction material 210 in a fourth step. Specifically, irradiation of a laser beam L is started on an exposed portion 205 of the core metal 201. A laser head 301 is displaced in an annular shape while continuously emitting the laser beam L. Thus, annular fine grooves 204 and 211 are formed in the exposed portion 205 of the core metal 201 and the friction material 210.