When one or more storage data are coincident with single search data, an associative memory carries out logical sum for all of storage data with a valid state for storage data as true. The permanent magnet module comprises: a stack of ferromagnetic steel sheets having a groove in the direction perpendicular to the ferromagnetic steel sheets, and a permanent magnet located in the groove and arranged to produce magnetic flux that penetrates a surface of the stack of ferromagnetic steel sheets. A drying module is operatively mountable with respect to the support frame and defines a first chamber and a second drying chamber. The spring defines a circumference while in the uncoiled configuration. The reference voltage controller generates an adjustable internal reference voltage by adjusting a ferroelectric capacitance, selectively switches the internal reference voltage and an external reference voltage applied from a pad, and outputs the selectively switched value as the reference voltage into the sense amplifier array unit.