Valve device

A valve device attachable to a wheel including a tire in a state where the valve device penetrates through an opening of the wheel. The valve device includes a transmitter unit for detecting a condition of the tire and generating a transmission signal indicating the detected condition of the tire, a valve stem extending from the transmitter unit and an elastic member disposed to surround the valve stem. The elastic member has an annular attaching portion having a diameter greater than the diameter of the opening. The valve stem is attached to the wheel by passing the attaching portion through the opening by compressively deforming the attaching portion. The attaching portion includes a recessed portion for facilitating compressively deforming the attaching portion.