A quick release device is provided for releasing a stretcher (1) for ambulance from a relative fastening or support surface (2) fixed to the walking surface of the ambulance. In the fastening (2), a releasable system (7) is provided for the stretcher (1) as well as a release mechanism controllable by means of a control device located in a housing (8). The quick release device (10) according to the invention comprises a curved tube (21), mounted in the lower part of the frame (3), in proximity to the housing (8) and movable between a rest position (R), in which said driving element (20) remains outside said housing (8), and a release position (S), in which the same abovementioned driving element (20) fits in the housing (8) in order to actuate the control device. Control means (25) for said driving element (20) are arranged in proximity to the grip (31) of the abovementioned stretcher (1) and can be actuated simultaneously with the controlled unloading of the stretcher, in order to bring said driving element (20) alternately between the rest (R) and release (S) positions.