To provide a base cloth sheet of a block mat which is hardly exfoliated and separated from a concrete block.

The base cloth sheet A includes a sheet body 1 and separate and independent loop threads 2 for forming loops on the sheet body 1. The base cloth sheet comprises the sheet body, lengthwise and crosswise insert threads attached onto the sheet body, chain threads connecting the insert threads to the sheet body, and loop threads forming loop parts being entwined with the lengthwise insert threads 4 and the sheet body. The insert threads, the chain threads 3 and the loop threads 2 are the threads separate and independent from the sheet body 1. The loop parts 21 are embedded in a concrete block to be fixed.