To provide a decorative panel for interior finishing, and its manufacturing method, which can prevent beauty from being deteriorated by a gap, and which can reduce labor and costs for working.

This decorative panel 10 for interior finishing comprises an upper layer part 12 with a decorative surface A, and a lower layer part 14 which is formed integrally with the upper layer part 12 below the upper layer part 12. Each side of the upper layer part 12 is made linear; each side of the lower layer part 14 is constituted by making a male tongue 16, which protrudes from each side of the upper layer part 12, and a female tongue 18, which is depressed from each side of the upper layer part 12, continue into each other via a boundary part 20; and the male tongue 16 and the female tongue 18 on each side are arranged in positions symmetric with respect to the center point of the lower layer part 14. In the manufacture of the decorative panel 10, an approximately square panel base material is prepared, and the male tongue 16 and the female tongue 18 are subjected to cutting work on each side of the panel base material by means of a rotary cutter.