In a bottle made of synthetic resin of the present invention, a handle is combined to a bottle body so that the bottle can be easily handled for carrying it and pouring the content. When the joint of the handle to the bottle body is unstable, it is difficult to handle the bottle and it will occur an accident when the handle comes off the bottle body. Therefore, in the present invention, a reinforcing structure is provided to necessary portions not to deform the joining portion of the handle to the bottle body and further a coming off-preventing mechanism is provided so that the handle does not comes off the bottle. The coming off-preventing mechanism is accomplished by a supporting projection and/or a supplementary engaging protruding portion and a supplementary engaging recess portion. To ensure the coming off-preventing mechanism, the bottle body is formed by biaxial oriented blow molding with assembly beams of the handle as an insert.