Abstract: A band clamping device which is constructed with a U-shaped main body with the bottom part thereof constituting a seating member, and with both sides extending from the seating member in the form of a channel being made to constitute a pair of support members; a flexible band, one end of which is folded for being hooked at the seating member through at least one slot formed therein; a band take-up member provided in one part thereof with a band insertion slot and which is rotatably held by said pair of support members; a ratchet wheel which rotates integrally with the band take-up member and a return preventive mechanism to cause an engaging pawl provided on the support member to be engaged with the ratchet wheel, wherein the angle of bending of the support members is made greater than 90.degree.