A throttle grip device comprising: an interlocking member, a magnetic sensor forming a rotation angle detecting unit, a return spring, a holding member and a case, said interlocking member capable of rotating with a rotational operation of a throttle grip of a vehicle, wherein said interlocking member has a fitted portion into which a fitting portion (Ga) of said throttle grip can be fitted, an accommodation recess for accommodating the return spring, a locking portion for locking one end of the return spring, and a stopper portion protruding at a predetermined position; said rotation angle detecting unit capable of detecting a rotation angle of said throttle grip by detecting a rotation angle of said interlocking member; and said return spring configured by a torsion coil spring which urges said throttle grip and said interlocking member in a rotation direction toward initial positions when said throttle grip is rotationally operated, wherein an engine of the vehicle can be controlled according to the rotation angle of said throttle grip detected by said rotation angle detecting unit, and said holding member rotatably holds said interlocking member while positioning said interlocking member and holds the other end of said return spring while locking the other end of said return spring, wherein said holding member has a guide portion formed to protrude in an annular shape, and said interlocking member is positioned by being rotatably fitted to said guide portion, wherein said holding member further has a locking portion for locking the other end of said return spring, and a holding portion held in contact with said interlocking member urged in the rotation direction by said return spring, and said locking portion is formed of a portion obtained by bending a part of said holding member. an interlocking member, a magnetic sensor forming a rotation angle detecting unit, a return spring, a holding member and a case, said interlocking member capable of rotating with a rotational operation of a throttle grip of a vehicle, wherein said interlocking member has a fitted portion into which a fitting portion (Ga) of said throttle grip can be fitted, an accommodation recess for accommodating the return spring, a locking portion for locking one end of the return spring, and a stopper portion protruding at a predetermined position; said rotation angle detecting unit capable of detecting a rotation angle of said throttle grip by detecting a rotation angle of said interlocking member; and said return spring configured by a torsion coil spring which urges said throttle grip and said interlocking member in a rotation direction toward initial positions when said throttle grip is rotationally operated, wherein an engine of the vehicle can be controlled according to the rotation angle of said throttle grip detected by said rotation angle detecting unit, and said holding member rotatably holds said interlocking member while positioning said interlocking member and holds the other end of said return spring while locking the other end of said return spring, wherein said holding member has a guide portion formed to protrude in an annular shape, and said interlocking member is positioned by being rotatably fitted to said guide portion, wherein said holding member further has a locking portion for locking the other end of said return spring, and a holding portion held in contact with said interlocking member urged in the rotation direction by said return spring, and said locking portion is formed of a portion obtained by bending a part of said holding member.