A fundus oculi observation device, comprising: a broadband light source configured to output a light; an interference-light generator configured to split the light from the broadband light source into a signal light and a reference light, and superimpose the signal light propagated through a fundus oculi and the reference light propagated through a reference object to generate an interference light; a detector configured to detect the interference light and generate a detection signal; an image forming part configured to form a tomographic image (G1-Gm) of the fundus oculi based on the detection signal by applying OCT technique; a manipulation part adapted to enable the operator of the device to set a cross-sectional position of a cross section of the tomographic image; a calculator configured to calculate layer thickness distribution of the fundus oculi in the said cross section of the tomographic image based on the tomographic image (G1-Gm); a specifying part configured to specify a vascular region (V1,V2) in the tomographic image based on the tomographic image (G1-Gm); a display; a controller configured to control the display to display layer thickness distribution information representing the layer thickness and to also display vascular position information (W1,W2) representing a position of the vascular region on the layer thickness distribution information; and wherein the controller is configured to display a graph having a horizontal axis defined along the cross section and a vertical axis taking layer thickness values, as the layer thickness distribution information, and display a vascular position image (W1,W2) representing a position of the vascular region as the vascular position information. a broadband light source configured to output a light; an interference-light generator configured to split the light from the broadband light source into a signal light and a reference light, and superimpose the signal light propagated through a fundus oculi and the reference light propagated through a reference object to generate an interference light; a detector configured to detect the interference light and generate a detection signal; an image forming part configured to form a tomographic image (G1-Gm) of the fundus oculi based on the detection signal by applying OCT technique; a manipulation part adapted to enable the operator of the device to set a cross-sectional position of a cross section of the tomographic image; a calculator configured to calculate layer thickness distribution of the fundus oculi in the said cross section of the tomographic image based on the tomographic image (G1-Gm); a specifying part configured to specify a vascular region (V1,V2) in the tomographic image based on the tomographic image (G1-Gm); a display; a controller configured to control the display to display layer thickness distribution information representing the layer thickness and to also display vascular position information (W1,W2) representing a position of the vascular region on the layer thickness distribution information; and wherein the controller is configured to display a graph having a horizontal axis defined along the cross section and a vertical axis taking layer thickness values, as the layer thickness distribution information, and display a vascular position image (W1,W2) representing a position of the vascular region as the vascular position information.