The present variety of mushroom plant named 'Hokuto Shiro Ichigoukin' was produced by crossbreeding mutant fungal strains of two parent varieties, a + variety 'Hokuto Hachigoukin' and a - variety 'Hokuto Jyunigoukin,' after UV irradiation. This edible mushroom is not bitter, and can be cultivated anywhere a cultivation facility can be arranged.