The present disclosure provides a reciprocating device which includes a base, a moving frame, a shaking unit, an adjustment unit, and a driving unit. The moving frame can reciprocate relative to the base. The shaking unit has a shaking assembly and a driven assembly. The shake of the shaking assembly enables the driven assembly to move, and the movement of the driven assembly enables the moving frame to reciprocate relative to the base. The adjustment unit has an adjustment assembly and a power member. The power member drives the adjustment assembly to change the position thereof, and the positional change of the adjustment assembly alters the way that the shaking assembly shakes to adjust the reciprocating range of the moving frame. Therefore, the moving frame of the present invention can reciprocate and the reciprocating range of the moving frame can be adjusted according to the user's preference, so that the present invention can help a user sleep and improve sleep quality.