PURPOSE: To reduce costs and eliminate irregularity caused by assembling by integrally molding an undercut part continuously from a main body simultaneously with molding of the main body of a ligneous molded piece so as to minimize the number of parts.

CONSTITUTION: A press molding device molds a ligneous molded piece 101 having a main body 102 and an undercut part 103 to be formed continuously from the end of the main body 102. The press molding device comprises a lower mold 1 where a ligneous material is set on a mold face 2, an upper mold 11 which is lifted and lowered from and to the lower mold 1 so as to open and close the molds, a lifting body 22 supported by the upper mold 11 movably up and down, and a mold face 25 which continues on a mold face 12 of the upper mold 11 arranged on the bottom face. The device also comprises a movable mold 24 having an undercut molding face 26 at the end face and being axially supported by the lifting body 22 rotatably, and a slide cam 16 which is supported by the upper mold 11 movably back and forth and is made to advance by a fixed cam 5 of the lower mold 1 with the descent of the upper mold 11 and has a mold blade 17 for the undercut molding face 26 of the movable mold 24 at the front end.