The invention relates to an accumulator device, in particular in the form of a piston accumulator, having a dividing piston (22) which inside an accumulator housing (2) separates two media chambers (26, 28) from each other, and in particular separates a chamber (28) containing a working gas, such as nitrogen, from a chamber (26) containing a working fluid, such as hydraulic oil. The invention is characterized in that the dividing piston (22) is longitudinally movably guided in a guide device (24) and that the guide device (24) is arranged inside the accumulator housing (2) and extends at least partially along the longitudinal axis (10) thereof.