In this paper the general equations of the plane linear viscoelastostatics are deduced. The elements of the stress and strain tensors are given by means of a pair of analytic functions, which depend on the space variable z and time r, the later appearing as a parameter. The definitions of two basic boundary-value problems are given as well as the proofs of the uniqueness theorems. The existence of the solutions is prooved by the transformation of the problem to the solution of Fredholm’s integral equation of the second order. When considering the second boundary-value problem it is necessary to introduce additional conditions of the operator $K$. Two examples of such operators are given, where the shown theory is entirely fulfilled.