An inkjet printer is provided, which is configured to acquire gap information related to a gap between an ink discharging surface and a recording sheet in each individual position of top-formed positions and bottom-formed positions within a predetermined wave-shape generating range, identify, when the predetermined wave-shape generating range includes a partial range in which the recording sheet is not placed, a top-formed position where the gap information has not been acquired and a bottom-formed position where the gap information has not been acquired, within the partial range, complement the unacquired gap information in the identified top-formed position with a value determined based on the respective pieces of gap information acquired in other top-formed positions, and complement the unacquired gap information in the identified bottom-formed position with a value determined based on the respective pieces of gap information acquired in other bottom-formed positions.