A method for manufacturing a double-walled box from a double-walled blank, the blank comprising: a first sheet for forming the inside of the box, and a second sheet for forming the outside of the box, the first sheet comprising a first set of crease lines extending at an angle in relation to a second set of crease lines for forming a first pair and a second pair of opposing inner side wall sections (112, 114), an inner bottom wall section and four inner corner sections, the blank further comprising four corner crease lines each extending in a respective inner corner section from a respective intersection between one crease line of the first set of crease lines and one crease line of the second set of crease lines to a corner associated with the inner corner section, the second sheet comprising a first set of crease lines extending at an angle in relation to a second set of crease lines for forming a first and a second pair of opposing outer side wall sections, an outer bottom wall section and four outer corner sections, wherein the second set of crease lines has terminal sections formed as slits, the method comprising: transferring the blank to a first position in a blank folding machine, such that the inner bottom wall section is positioned above an opening with the first sheet facing away from the opening, engaging from above each inner corner section by a corner section securing device, pushing down the inner bottom wall section into the opening by a plunger, wherein the step of the pushing down comprises: a first phase during which the blank is moved from the first position to a second position and in which a first engagement member folds the first pair of opposing inner side wall sections for initiation of erection thereof while maintaining the engaging from above for controlling folding about the four corner crease lines, a second phase in which the blank is moved from the second position into a third position and in which a second engagement member folds the second pair of opposing inner side wall sections for erection thereof, a third phase in which the blank is kept in the third position and in which a corner engagement member folds the inner corner sections such that each inner corner section is folded about one crease line of the first set of crease lines and/or one crease line of the second set of crease lines for formation of flaps which are pressed against the inner side wall sections (112, 114), and a fourth phase in which the blank is moved from the third position into a fourth position in which a third engagement member engages the first pair of opposing outer side wall sections for erection thereof. transferring the blank to a first position in a blank folding machine, such that the inner bottom wall section is positioned above an opening with the first sheet facing away from the opening, engaging from above each inner corner section by a corner section securing device, pushing down the inner bottom wall section into the opening by a plunger, wherein the step of the pushing down comprises: a first phase during which the blank is moved from the first position to a second position and in which a first engagement member folds the first pair of opposing inner side wall sections for initiation of erection thereof while maintaining the engaging from above for controlling folding about the four corner crease lines, a second phase in which the blank is moved from the second position into a third position and in which a second engagement member folds the second pair of opposing inner side wall sections for erection thereof, a third phase in which the blank is kept in the third position and in which a corner engagement member folds the inner corner sections such that each inner corner section is folded about one crease line of the first set of crease lines and/or one crease line of the second set of crease lines for formation of flaps which are pressed against the inner side wall sections (112, 114), and a fourth phase in which the blank is moved from the third position into a fourth position in which a third engagement member engages the first pair of opposing outer side wall sections for erection thereof. a first phase during which the blank is moved from the first position to a second position and in which a first engagement member folds the first pair of opposing inner side wall sections for initiation of erection thereof while maintaining the engaging from above for controlling folding about the four corner crease lines, a second phase in which the blank is moved from the second position into a third position and in which a second engagement member folds the second pair of opposing inner side wall sections for erection thereof, a third phase in which the blank is kept in the third position and in which a corner engagement member folds the inner corner sections such that each inner corner section is folded about one crease line of the first set of crease lines and/or one crease line of the second set of crease lines for formation of flaps which are pressed against the inner side wall sections (112, 114), and a fourth phase in which the blank is moved from the third position into a fourth position in which a third engagement member engages the first pair of opposing outer side wall sections for erection thereof.