To provide a manufacturing method for forming an outer shell frame of an inverted pendulum type movable body with a high degree of accuracy.

The manufacturing method is intended to produce the lower frame of the inverted pendulum type movable body 1 equipped with a lower frame 22 made of carbon fiber reinforced plastic and a traveling unit 3 provided in the lower frame. The method is characterized by including: a step in which the carbon fiber reinforced plastic is hardened in a lower mold 100 and an upper mold 120 so as to form a molded article 300; a step in which the molded article is fitted into the lower mold or the upper mold; a step in which the molded article is fixed to the lower mold or the upper mold using a fixing member 145; a step in which the lower mold or the upper mold to which the molded article is fixed is positioned and fixed on the work table 601 of a numerically-controlled machine tool 600; and a step in which the molded article is machined using the numerically-controlled machine tool so as to form an attachment part 38L, 38R of the traveling unit in the molded article.