In a lamp unit for a vehicle, light incident into a translucent member from a light emitting element is reflected by the inner surface of the translucent member reflecting surface and irradiated from the irradiating surface of the translucent member in the forward direction of the lamp unit. The reflecting surface is vertically shaped as a concave curved formed by a hyperbola. The focusing point is the light emitting center of the light emitting element, whereby the reflecting light is irradiated as spread light from the virtual image position of the light emitting element formed by the reflecting surface within the vertical section. The irradiating surface is vertically shaped as a convex curve formed by an ellipse which focusing point is the virtual image position. The irradiating light can be made substantially parallel rays within the vertical section.