An HMD apparatus includes an image source, a light guiding element, a first modulating element, and a second modulating element. The image source provides an image beam. The light guiding element is arranged on a transmission path of the image beam to transmit the image beam. The light guiding element has a first surface and a second surface opposite to each other. The image beam undergoes total internal reflection at the first surface and is emitted from the second surface. The first modulating element is arranged on one side of the first surface of the light guiding element and configured to adjust a transmittance of an ambient beam. The light guiding element is arranged between the first and second modulating elements, and the second modulating element is configured to adjust a focus position of the image beam. The HMD apparatus may improve wearing comfort and achieve good display effects.