The head mounted display includes: a headgear having an attachment that comes into close contact with the face of the user in a manner such that the user can see at least the front and a fixture that is attached to the attachment and is used for fixing the attachment to the head of the user while maintaining the close contact with the face of the user; a display unit that has a video display unit configured to display video and is detachable from the attachment; and a lock mechanism that is provided in at least one of the attachment or the display unit, and fixes the display unit to the attachment in a manner such that the fixing can be released. The attachment and the display unit are configured to engage with each other in the front-rear direction of the user.