An improvement is achieved in the performance of a semiconductor device. A second component mounting portion over which a first electronic component is mounted is connected to a coupling portion of a lead frame via a suspension lead. The suspension lead has a first portion between the second component mounting portion and the coupling portion and a second portion between the first portion and the coupling portion. The second portion has a third portion connected to the first portion and having a width smaller than a width of the first portion, a fourth portion connected to the first portion and having a width smaller than the width of the first portion, and a through hole (opening) located between the third and fourth portions. Each of the first, third, and fourth portions has the same thickness. After a sealing body is formed, a cutting jig is pressed against the suspension lead to cut the suspension lead.