A nozzle testing device includes: a two-dimensional image sensor to capture an image of a pattern formed on a recording object by discharging ink from a nozzle row while moving the nozzle row and the recording object relative to each other in a direction orthogonal to the nozzle row; a light source unit provided such that regularly reflected light by the pattern forms a regular reflection area in the image of the pattern captured by the two-dimensional image sensor; and a detection unit to analyze the image to detect discharge failure of the nozzles. The regular reflection area is formed in the image such that a dimension in a direction corresponding to the direction of relative movement between the nozzle row and the recording object is greater than a dimension in a direction orthogonal to the direction corresponding to the direction of relative movement in the image.