An initiating device including at least one detonator, at least one booster charge and an action charge. The at least one booster charge is arranged such that, at the action charge initiates, the booster charge is free from disturbing edge effects that can have a disturbing effect on the action charge. A booster casing in which the booster charge is disposed is configured with a rear cylindrical part having a diameter D1, a front conical part delimited by a first circular limit face having the diameter D1, and a second circular limit face having a diameter D2, wherein the two limit faces are plane-parallel at a distance H1 from each other, wherein H1/D2 lies within a range 0.5-1.5. Also, a production method for producing the booster charge.