Head mounted display device and strap module thereof

A head mounted display device, comprising:

• a host;
• a strap module, comprising;
• a casing having a first slide rail and a second slide rail;
• a first strap having a first terminal and a first connecting section;
• a second strap having a second terminal and a second connecting section, wherein the first terminal and the second terminal are respectively connected to two opposite sides of the host, and the first connecting section and the second connecting section are at least partially overlapped and accommodated in the casing;
• a first speaker module slidably disposed on the first slide rail;
• and
• a second speaker module slidably disposed on the second slide rail,
• wherein the first connecting section has a first magnetic portion, the second connecting section has a second magnetic portion, the first speaker module has a third magnetic portion, the second speaker module has a fourth magnetic portion, and when the first connecting section and the second connecting section slide in the casing, the first magnetic portion magnetically attracts the third magnetic portion to drive the first speaker module to slide on the first slide rail, and the second magnetic portion magnetically attracts the fourth magnetic portion to drive the second speaker module to slide on the second slide rail.