An injected dose detection device including a housing having a joint surface surrounding an injection device, a vibration sensor disposed in an internal part of the housing configured to detect at least one vibration signal of a dose-setting action based on a minimum vibration threshold, an acoustic sensor disposed in the internal part of the housing configured to detect at least one dosage click of the dose-setting action, a vibration transmitting element positioned directly between the vibration sensor and the injection device and configured to transmit the at least one vibration signal and a processing unit configured to process the at least one vibration signal from the dose-setting action and the at least one dosage click from the dose-setting action for generating set dose information corresponding to the injected dose wherein a bottom plate and a side wall of the vibration transmitting element form a shell structure to cover the vibration sensor.