Non-primary explosive detonator comprising a hollow tube (1) with a closed end having a chamber containing a secondary explosive base charge (8), an opposite open end provided with or for the insertion of an igniting means (9, 15, 16), and an intermediate confinement adjacent said chamber and containing an initiating charge (7), a delay composition (6) optionally being present adjacent said initiating charge. The characteristic feature of the detonator is that the confinement contains a secondary explosive initiating charge (7), by which the current drawbacks in connection with primary explosive initiating charges are reduced, and that it is thin-walled and in the end towards said chamber is open or provided with a thin wall or an aperture (5) or a recess therefore, to accelerate the burning of said secondary explosive initiating charge to a shock wave that causes detonation of said secondary explosive base charge, and a hole (4) which permits ignition of said secondary explosive initiating charge via the igniting means (9). By the special design of the confinement the detonator is very versatile as compared to previously known non-primary explosive detonators. The invention also relates to a separate initiating element having the structure disclosed above for the confinement.