Disclosed is an illuminating apparatus including a housing including a lower plate and a side plate and a light emitting module including a substrate disposed on the lower plate and a plurality of light sources disposed on the substrate to be spaced apart from each other, wherein a height of the side plate is determined as a value obtained by dividing a separation distance between adjacent ones of the light sources by a value obtained by multiplying a tangent value of a max intensity angle of each of the light sources by a luminance compensation factor.