A tire pressure monitoring device with an inclinable valve stem is disclosed. The tire pressure monitoring device includes: a main body having a channel, wherein the channel includes a socket segment near one end thereof; the valve stem being movably fixed to a wheel rim and having a domed end movably received in the socket segment wherein the domed end has a threaded hole axially passing therethrough; and a positioning bolt being positioned in the channel from an opposite end of the channel and coupled with the threaded hole, so that the domed end of the valve stem is movably positioned in the socket segment and when the domed end moves, an angle between the connected valve stem and the main body is changed, thereby allowing the main body to abut against the wheel rim.