The new renonnalization procedure in quantum electrodynamics is presented in this paper. With this procedure, the finite S-matrix can be automatically obtained by· use of the modified commutation relations and propagation functions and, therefore, without introducing the counter tenns of mass- and charge-types. The various significant features of this new renonnalization procedure are also discussed. § 1. Introductiou and summary As is well known, in the theory of the S-matrix in quantum electrodynamics there appear four infinite constants (ax,~, Z2 and Z:I).1) The contributions of Zl and Z2' however, cancel each other in virtue of the Ward's identity ~=Z22), and so the infinities remaining in the final expression of S-matrix are those of ax and Z:l' which are regarded as the induced mass and charge due to the reaction of the self-field. In the usual renormalization theory these two infinities are removed by means of the counter terms of mass and charge. In the present paper the new renormalization method is presented, in which the introduction of such counter terms is unnecessary. As is well known, the diverging term iJx of the mass type of the electron can be eliminated by means of a canonical transformation, which leads to the result of changing the mass Xo into Xo + ox. Therefore, it is expected that without introducing the counter terms of mass type we can eliminate the diverging term by using the commutation relation of the electron field with the mechanical mass xo=x-ax (and so the propagation function S I (xo» and regarding x as the finite, observable mass. * The charge renormalization term Zs changes the original charge e into the observable charge e1• This effect amounts to regarding the vacuum as the polarizable medium with the field independent polarizability. Therefore, this type of divergence may be removed by starting with the Lagrangian function of the electromagnetic field in the medium having the constant polarizability. As is ·evident from the argument of covariance, the Lagrangian function of the electromagnetic field in such a medium has the same form as the usual one excepting the constant numerical factor, and so the commutation relations of electro­ magnetic potentials AfJ.'s is modified by the inverse ratio of this constant factor (cf. § 2. 1). Thus, we can expect that the infinite term can be removed by using such a com­ mutation relation and without using the counter term as was introduced by Gupta.3) ... This expectation was previously pointed out in connection with the treatment of the meson cloud: