A method (40) for producing a cobalt sulfate crystal, which is performed for obtaining crystals of a cobalt sulfate heptahydrate from a cobalt sulfate-containing aqueous solution, the method includes a crystallization step (10) of subjecting a cobalt sulfate-containing aqueous solution (11) to evaporative concentration to obtain a slurry (12) containing cobalt sulfate crystals, a separation step (20) of subjecting the slurry (12) obtained in the crystallization step (10) to solid-liquid separation to obtain a dewatered cake (21) of the cobalt sulfate crystals, and a drying step (30) of drying the dewatered cake (21) obtained in the separation step (20) by a flash drying of bringing the dewatered cake (21) into direct contact with a drying medium (31) to obtain the cobalt sulfate crystals (41).