To obtain a sheet that biodegrades into a material existing in the natural kingdom by laying the sheet in soil or compost after use, does not cause the environmental pollution and exhibits excellent flame retardance.

The biodegradable sheet for construction work is obtained by treating 100 parts wt. of a woven or knitted fabric of a biodegradable resin with a biodegradable flame retardant liquid mixed with a biodegradable resin emulsion so as to have 0-20 parts wt. solid content, impregnating and sticking 5-50 parts wt. of the solid content of the liquid to the woven or knitted fabric, heating and drying the woven or knitted fabric, immersing and sticking a biodegradable resin emulsion incorporated with 0-50 parts wt. of a biodegradable flame retardant to the 100 parts wt. of the heated or dried flame-retarded woven or knitted fabric of a biodegradable resin so as to give 3-70 parts wt. solid content, coating the surface of the fabric and drying and heating.