The disturbance to a temperature field in the earth's crust due to dike intrusion is studied as a continuation of a previous paper (Hoˆrai (1974)). As in part 1, the earth's crust is assumed to be a two-dimensional isotropic, homogeneous, semi-infinite medium with constant thermal conductivity and zero surface temperature. In part 1 the dike is approximated by an isotherm of rectangular shape with temperature T0 and width 2B, extending vertically from depth D to depth H. In the present paper a case H=∞ is studied: namely; the dike is approximated by an isotherm of rectangular shape with temperature T0 and width 2B, extending vertically from depth D to infinity. By the method of conformal mapping, mathematical formulas are developed to describe isotherms, flow lines, and surface heat flow as a function of parameters specifying the intrusion, i.e., T0, D, and B. Relationships among the parameters that specify the dike (T0, D, B) and the heat flow anomaly (peak height Qm and width x&ggr;) are illustrated. The formula of surface heat flow obtained in the present paper is not identical with that obtained by Von Herzen and Uyeda. It is shown that the latter formula of surface heat flow does not correpond to a dike represented by a rectangular isotherm.