NOVELTY - A non-burning layer, dry-distillation layer, burning layer, and charring layer of straw are formed. The burning layer heats and dry-distils the dry-distillation layer to decompose volatilization portion, which is absorbed into the burning layer to carry out burning. Smoke produced by the burning layer is absorbed into the charring layer under the burning layer to char straw. Air is absorbed into the charring layer, smoke is led out, and the burning layer is moved from bottom up with the charring process. Thus, straw charcoal is obtained.    USE - Preparation of straw charcoal used for preparing barbecue-type charcoal (all claimed).    ADVANTAGE - The method enables preparation of straw charcoal which provides both fast-burning and slow-burning barbecue-type charcoal. Since the barbecue-type charcoal does not use wood carbon, it is economical and eco-friendly.    DETAILED DESCRIPTION - A non-burning layer, a dry-distillation layer, a burning layer, and a charring layer of straw are formed from top to bottom. The burning layer heats and dry-distills the dry-distillation layer nearby upward side heat to decompose volatilization portion. The volatilization portion is absorbed into the burning layer to carry out burning. Smoke produced by the burning layer is absorbed into the charring layer under the burning layer in order to supply heat quality needed to char straw on the charring layer. Air is continuously absorbed into the charring layer from top of the non-burning layer, smoke is led out from lower portion after passing through the charring layer, and the burning layer is moved from bottom up with the charring process. Thus, straw charcoal is obtained. INDEPENDENT CLAIMS are included for the following:    (1) charring device consisting of charring tanks with sidewall and bottom, a gas channel set at the bottom, a horizontal smoke-separating channel set under the gas channel in order to collect gas from the gas channel, a smoke-collecting channel connected to the smoke-separating channel in order to collect smoke from the horizontal smoke-separating channel from which smoke is discharged to external, and a gas flow regulating device set on the smoke-collecting channel;    (2) barbecue-type charcoal prepared using the straw charcoal. The preparation of barbecue-type charcoal comprises: (a) charcoal material which is straw charcoal, or mixture of straw charcoal or other charcoal-containing material, (b) ignition powder which is oxidant, the content is as follows: based on theoretical oxygen consumption when the charcoal material burns completely, the content makes that the oxygen-enriched coefficient of the straw charcoal is not less than 0% or not more than 3.5%, (c) clean additive which is metal oxide, metal carbonate, metal nitrate, and/or metal hydroxide, the metal being alkali-earth metal or alkali metal, the dosage being such that it can set the equivalent proportion of alkali metal to sulfur molecule in charcoal material to 1-2, preferably 1.4-1.6, and (d) binder which is starch, with the additional amount being set to make the weight ratio of other component of the barbecue-type charcoal except the binder to the binder to 100:2-4; and    (3) preparation of barbecue-type charcoal, which involves: (a) mixing the components according to the proportion, (b) crushing the prepared materials till the granularity is more than 0 and not more than 4 mm, (c) uniformly mixing crushed mixture, kneading and blending, (d) using roll-type molding machine to press the product to form balls, or using spiral extruder or press molding machine to press the product to form rod shape or honeycomb shape, and (e) drying and consolidating the molded product.