PURPOSE: To simply change size of paste product formed so as to cover a core ingredient by converting the circumference of the core ingredient as a solid material with a pasty raw material while pushing out the core ingredient downward by a pushing tool and cutting the pasty raw material at the top of the core ingredient by an opening and closing shutter.

CONSTITUTION: A core ingredient as a solid material is supplied to an inner cylinder 5 and a pasty raw material is sent from a feed pipe 1 of the raw material to an outer cylinder 4. The raw material is delivered from the outer cylinder during opening of an opening and closing shutter 8, the core ingredient is simultaneously pushed shutter 8, the core ingredient is simultaneously pushed out by a core ingredient pushing tool 15 and the opening and closing shutter is closed to cut the pasty raw material. The size of formed paste product is changed by controlling an amount of the pasty raw material sent from the outer cylinder under pressure and opening and closing speed of the opening and closing shutter.