The invention aims to provide a highly heat conductive tape member or sheet member and a method for easily producing a highly heat conductive tape member or sheet member. The mica tape member or mica sheet member of the invention includes a mica-containing layer and a lining material, and the mica-containing layer contains scaly particles, particles having a heat conductivity of 0.5 W/mK or higher and a size of 1 .mu.m or smaller, and a binder.