To efficiently carry out compression packing of a mattress with a wide area in small equipment during compression packing of a cushion material.

The mattress 1 is inserted into a bag 4 having airtightness, and then the bag 4 with the mattress 1 is sent into a pair of rollers 5a, 5b to be urged to approach to each other and is compressed from the side of a closing d of the bag 4 toward the side of an opening f thereof. When a portion near the opening f of the bag 4 is sandwiched by the pair of the rollers 5a, 5b after the mattress 1 passes the pair of the rollers 5a, 5b, the interior surface of the bag 4 is hermetically sealed and the portion near the opening of the bag 4 is sealed with a fusion device 7.