To provide an anti-theft device for vehicle which is free of interference of a trick behavior and obstacle from outside, and which can be easily assembled.

Immobilizer unit 14 and an antenna 13 are integrally formed, and a main switch 12 and the immobilizer unit 14 are integrally assembled to form an assembly A. Then, the antenna part of the immobilizer unit 14 is inserted into an annular attachment part 1d of a handle bracket 1 and clamped and fixed by a clamping device, and the immobilizer unit 14 is arranged between the annular attachment part 1d of the handle bracket 1 and the main switch 12. The main switch 12 and the antenna 13 are integrated, and the main switch 12 and the immobilizer unit 14 are integrally assembled to form the assembly A. Then, the antenna part of the main switch 12 is inserted into the annular attachment part 1d of the handle bracket 1 and clamped and fixed by the clamping device, and the immobilizer unit 14 is arranged between the annular attachment part 1d of the handle bracket 1 and the main switch 12.