PURPOSE: To reduce the manufacturing cost and construction cost of an RC construction column and its construction property by joining a tubular mold form for covering the outer peripheral portion of a column steel to a column mold form by plural sets, the column mold form being formed by beam steal joints protruded to the circumference of the tubular mold form, and building the plural sets on a reinforcement cage.

CONSTITUTION: A plurality of column steels 11 annularly arranged at intervals in their longitudinal direction, and a hoop steel 12 serving as a band steel for binding the steels 11 in their cross direction are provided. A mold form 10 for an RC construction column is comprised of a tubular mold form 13 for covering the outer peripheral portion of the column steels 11, and plural beam steel joints 14 each penetrating the inside of the mold form 13 and protruding to the ambience. A reinforcement cage 22 for columns is installed on the bottom portion of a pile hole 21 and mold forms 10 are built on the reinforcement cage 22 by the number of underground floors while being joined to each other in their longitudinal direction. A tremie pipe 24 is built at the center of the mold form 10 and concrete is placed into the reinforcement cage 22 through the pipe 24. After initial hardening concrete is placed into the mold form 10 while pulling up the pipe 24, and an RC construction column 28 is constructed.