The invention relates to a dosing device designed to equip a container including a deformable reservoir containing a product. The device includes an insert that includes a dosing chamber that can be deformed by pressure from the product coming from the reservoir. The dosing chamber includes a top valve for the intake of the product from the reservoir, a bottom valve dispensing the product, and a deformable body connecting the top valve and the bottom valve. The dosing chamber is configured such that, under pressure from the product coming from the reservoir, the top valve is closed by the deformation of a first portion of the chamber, the bottom valve remaining closed, whereupon, the bottom valve opens under the effect of the deformation of the body.