A fuel carburetor includes a fuel passage, a heat medium passage, a space part, and an absorbent material. Ammonia as fuel flows through the fuel passage. The heat medium passage is arranged adjacent to the fuel passage, and a heat medium flows through the heat medium passage. Ammonia gas leaking out of the fuel passage flows into the space part. The absorbent material is provided in the space part for absorbing the ammonia gas. The fuel carburetor is configured to exchange heat between the fuel flowing through the fuel passage and the heat medium flowing through the heat medium passage so as to heat and vaporize the fuel.