A clamp for adjustably joining the ends of a strap having ends. The clamp has top and bottom members, and at least one of the top and bottom members has a groove extending from one side to the other side of the clamp. The groove receives the ends of the strap so first portions of the ends of the strap are within the groove and at least one other second portion of the strap extends outward from the sides of the clamp. Complementary aligning portions are located on the top and bottom members to align the top and bottom members to capture the first portions of the ends of the strap by friction within the groove formed within the clamp. The length of the strap is adjusted by the second portion of the strap that extend outward from the sides of the clamp.

A belt adjusting and holding device includes: a device body including a belt insertion part allowing insertion of a belt and an opening section communicating with the belt insertion part; and a belt folding member including a grasping part and a folding-back part to fold back the belt within the opening section. The belt folding-back member is configured to move forward and backward within the device body. Standing wall portions rising in a stepped shape are formed on the upper and lower inner wall surfaces of the belt insertion part. The belt folding-back member is formed with a protrusion, which substantially stepwisely bends the belt between the protrusions and the standing wall portions at a backward position of the belt folding-back member and release the belt at a forward position of the belt folding member.

A belt adjusting and holding device includes: a device body including a belt insertion part allowing insertion of a belt and an opening section communicating with the belt insertion part; and a belt folding member including a grasping part and a folding-back part to fold back the belt within the opening section. The belt folding-back member is configured to move forward and backward within the device body. Standing wall portions rising in a stepped shape are formed on the upper and lower inner wall surfaces of the belt insertion part. The belt folding-back member is formed with a protrusion, which substantially stepwisely bends the belt between the protrusions and the standing wall portions at a backward position of the belt folding-back member and release the belt at a forward position of the belt folding member.