A bonding method for a flexible display device, the method including arranging at least two bonding objects and an anisotropic conductive film (ACF) at a bonding position; applying a predetermined pressure to the at least two bonding objects and the ACF; and irradiating a laser beam at the bonding position to bond the at least two bonding objects and the ACF, a temperature and viscosity of the ACF being changed, and a change of the temperature following a predetermined temperature profile.