A solution-type preparation of lurasidone comprising N-[4-[4-(1,2-benzisothiazol-3-yl)-1-piperazinyl]-(2R,3R)-2,3-tetramethylene-butyl]-(1R,2S,3R,4S)-2,3-bicyclo[2,2,1]heptanedicarboxyimide hydrochloride (lurasidone) as an active ingredient and containing at least one substance selected from benzyl alcohol, N,N-dimethylacetamide, lactic acid and propylene glycol.