Provided is a phased array transmission device including: a plurality of transmission branches, each being provided with a phase shift unit that applies a phase rotation to a baseband signal, a DC offset correction unit that adds a first correction value to an output signal of the phase shift unit, and a mixer that subjects an output signal of the DC offset correction unit to a frequency conversion to a high frequency band; and a correction control unit that calculates a second correction value with which a carrier leak component included in an output signal of the mixer is minimized, for each of a plurality of candidates for a phase rotation amount that is set for the phase rotation, and determines the first correction value on the basis of the second correction value.