PURPOSE: To enable preparation of lawn in a free place without need of waiting for root taking of the lawn by preparing a lawn mat from lawn reared so as to entwine roots thereof with a mat base and covering the ground over with the resultant lawn mat.

CONSTITUTION: A mat base 1 is used to rear lawn so as to entwine roots thereof with the mat base 1. Lawn mats 10 are prepared from the aforementioned lawn and the ground is covered over therewith to prepare the objective lawn. Since the lawn already takes roots in soil in the mat base and reared, there is no (hardly any) need of waiting for root taking of the lawn in preparing the lawn. Furthermore, the lawn can be prepared in a free place with a sense to place flowerpots.