Back brace having pull cord for size adjustment

A back brace comprising:

• a first brace member including a first belt body made of a flexible material, and a first connector mounted on one side of said first belt body;
• a second brace member including a second belt body made of a flexible material, a second connector mounted on a first side of said second belt body, and a coupler mounted on a second side of said second belt body opposite to first side of said second belt body and detachably connectable to said first connector of said first brace member;
• a first adjustment holder including a first holder body mounted on said first belt body and provided at an inside thereof with a plurality of first protrusions spacedly arranged, and a first rod member supported on said first protrusions and defining with said first protrusions a plurality of first insertion holes, said first holder body having a plurality of openings in communication with said first insertion holes;
• a second adjustment holder including a second holder body mounted on said second belt body and provided at an inside thereof with a plurality of second protrusions spacedly arranged, and a second rod member supported on said second protrusions and defining with said second protrusions a plurality of second insertion holes, said second holder body having a plurality of openings in communication with said second insertion holes;
• at least one pull cord inserted through said first adjustment holder and said second adjustment holder and alternately running through said first insertion holes and said second insertion holes in a zigzag manner around said first rod member and said second rod member, said pull cord having two opposite ends respectively extending out of said first holder body and said second holder body;
• and
• two fastening members respectively affixed to the two opposite ends of said pull cord and detachably connectable to said first connector and said second connector.