A suspension device for supporting a mattress comprising: a base part comprising slots for attachment to a bedding structure; a top part comprising slots for receiving slats therein; a spring element provided between the base and the top part for resiliently suspending the slats in view of the bedding structure, whereby the spring element comprises at least: • a first spring element extending between the base part and the top part of the device; and • a second spring element extending between the base part and the top part of the device; and • an adjustable member allowing adapting the spring characteristic of the suspension device, characterised in that said second spring element comprises a first spring portion fixed to the base part and extending towards the top part ; a second spring portion fixed to the top part and extending towards the base part ; and a bridge portion connecting the free ends of the first and second spring portions (6a & 6b), whereby the first and second spring portions are spaced apart in a direction perpendicular to the suspension direction and the bridge portion defining an abutment surface and in that the adjustable member is movable in a guide or series of slots provided in the top part and comprises an actuating member that is in contact with the abutment surface , such that repositioning the adjustable member in said guide or series of slots changes the contact position of the actuating member along the abutment surface , thereby varying the spring characteristic of the device. a base part comprising slots for attachment to a bedding structure; a top part comprising slots for receiving slats therein; a spring element provided between the base and the top part for resiliently suspending the slats in view of the bedding structure, whereby the spring element comprises at least: • a first spring element extending between the base part and the top part of the device; and • a second spring element extending between the base part and the top part of the device; and • an adjustable member allowing adapting the spring characteristic of the suspension device, • a first spring element extending between the base part and the top part of the device; and • a second spring element extending between the base part and the top part of the device; and • an adjustable member allowing adapting the spring characteristic of the suspension device, characterised in that said second spring element comprises a first spring portion fixed to the base part and extending towards the top part ; a second spring portion fixed to the top part and extending towards the base part ; and a bridge portion connecting the free ends of the first and second spring portions (6a & 6b), whereby the first and second spring portions are spaced apart in a direction perpendicular to the suspension direction and the bridge portion defining an abutment surface and in that the adjustable member is movable in a guide or series of slots provided in the top part and comprises an actuating member that is in contact with the abutment surface , such that repositioning the adjustable member in said guide or series of slots changes the contact position of the actuating member along the abutment surface , thereby varying the spring characteristic of the device. <EOS>