An earphone for hearing protection unit comprises an earphone first portion for separating and facing a wearer and a partition wall (1) of an earphone second portion facing the environment. Further, the earphone comprises a loudspeaker (2) in the earphone first portion and an electrical connector (3) in the earphone second portion. The loudspeaker (2) is arranged in a loudspeaker holder (4). The loudspeaker holder (4) is provided with a first chamber (44) facing the wearer to seal a resonance space (8) and is disposed on the partition wall (1) above a first hole (13) in the partition wall (1). The loudspeaker holder (4) includes a film (42) above the first hole (13). The loudspeaker (2) and the electrical connector (3) are connected through an electrical wire (31). The electrical wire freely penetrates the first hole (13) from the partition wall (1) or penetrates another independent hole (131) from the partition wall (1). The loudspeaker holder (4) and the electrical wire (31) are connected in an airtight manner.