The present invention relates to a method of producing a powdered grain mixture which allows users to take nutritionally excellent shiitake mushroom or Angelica Utilis Makino together with mixed grains and removes foreign substances in the grains using a two-phase process to produce a clean and safe powdered grain mixture, and to the powdered grain mixture produced thereby. Accordingly, the method of producing the powdered grain mixture of the present invention comprises: (S10) a first step of removing foreign substances such as stones mixed with grains and shiitake mushroom (S20) a step of washing the grains and shiitake mushroom whose foreign substances are removed in the S10 step (S30) a step of drying the grains and shiitake mushroom washed in the S20 step (S40) a step of mixing the grains and shiitake mushroom dried in the S30 step to produce the grain mixture (S50) a step of powdering the grain mixture produced in the S40 into a predetermined size (S60) a step of secondly removing the foreign substances such as iron powder from the grain mixture powdered in the S50 step and (S70) a step of dividing the grain mixture whose foreign substances are removed in the S60 step into a predetermined amount and packing the divides, wherein the grains mixed in the S40 step includes one or more among black rice, brown rice, glutinous rice, barley and sorghum, and 10 to 30 parts by weight of shiitake mushroom relative to the 100 parts by weight of the selected grain types is comprised in the grain mixture.COPYRIGHT KIPO 2016본 발명은 영양학적으로 우수한 표고버섯 또는 함초를 혼합곡식과 혼합하여 함께 섭취할 수 있도록 하고, 곡식의 이물질을 2 단계에 걸쳐 제거함으로써 깨끗하고 안전한 분말 혼합곡식을 제조하는 방법 및 그에 의해 제조된 분말 혼합곡식에 관한 것이다.상기 목적을 달성하기 위한 본 발명의 분말혼합곡식의 제조방법은, 곡식 및 표고버섯에 섞여있는 돌을 포함하는 이물질을 1차 제거하는 단계(S10) 상기 S10 단계를 통해 이물질이 제거된 곡식 및 표고버섯을 세척하는 단계(S20) 상기 S20 단계를 통해 세척된 곡식 및 표고버섯을 건조하는 단계(S30) 상기 S30 단계를 통해 건조된 곡식 및 표고버섯을 골고루 혼합하여 혼합곡식을 제조하는 단계(S40) 상기 S40 단계를 통해 제조된 혼합곡식을 일정 크기의 범위로 분말화하여 분말혼합곡식을 제조하는 단계(S50) 상기 S50 단계를 통해 형성된 분말혼합곡식으로부터 쇳가루를
