In a manufacturing method of a tailored blank including a first steel plate and a second steel plate to be joined by butt welding, the first and second steel plates are butt welded with a laser beam. The laser beam has a power density q1 in a first region, a power density q2 in a second region, a power density q3 in a third region, and a power density q4 in a fourth region. The power density q1, the power density q2, the power density q3, and the power density q4 satisfy a relationship of q1>q2>q3>q4.