[en] In order to find a massive tensor field theory which tends to massless limit smoothly, canonical quantization of massless tensor field is carried out in general covariant gauges. To specify a gauge, three auxiliary fields are introduced. Generally there appears a gauge independent parameter b which plays an important role in the quantization procedure. When b not equal 1 four-dimensional commutation relations among fields can be derived through a straightforward extension of the method devised for quantum electrodynamics. There exists a massive tensor theory which connects with massless one, although Lagrangian does not coincide with the Fierz-Pauli one when the auxiliary vector fields are absent. When b=1 it is necessary to introduce scalar fields in addition to the vector fields and to follow the method of Dirac's new Poisson bracket. In this case another gauge independent parameter β appears in propagator for graviton and affects the interaction between matters. It is shown that in the case with b=1 and β= infinity, there exists not only a massless tensor theory consistent with experimental facts but also a massive theory which tends to the massless one smoothly. (auth.)