PROBLEM TO BE SOLVED: To provide hydrated β-maltose crystal-containing powder having excellent solubility in water and capable of being easily handled, to provide a method for producing the same by using a spraying process, and to provide compositions containing the same. SOLUTION: This hydrated β-maltose crystal-containing powder is produced by forming a maltose-containing solution into massecuite, spraying the massecuite to form powder, keeping the powder in an atmosphere of a low humidity and a high temperature, and further keeping it in another atmosphere of a high humidity and a low temperature, so that the powder contains the maltose in an amount of not less than 86% but less than 93% as an anhydrous state and glucose in an amount of not less than 2%, and has crystallinity of not less than 62% but less than 72%. Further, the powder contains an α-anomer in the maltose as an isomer of the maltose in an amount of not less than 7% but less than 14%. The powder thus produced has the excellent solubility in water, has good fluidity, is easily handled, and therefore is suitably used for the compositions of various kinds such as food and drink, cosmetics, and medicaments.