A compressor housing for a turbocharger, which is composed of a scroll piece, a shroud piece, and an outer-circumferential annular piece. The scroll piece includes a through part constituting a discharge port, a first intermediate wall surface extended from an intake-side wall surface of a scroll chamber and smoothly connected with the discharge port, and a scroll outer-circumferential part. The outer-circumferential annular piece includes an outer-circumferential annular press-fit part press fitted into the scroll outer-circumferential part, and a protruding part bent from an outer-circumference-side wall surface of the scroll chamber. The protruding part is inserted into the through part to form an inner wall surface of an intermediate part that communicates the discharge port with the scroll chamber. Then, the compressor housing is fixed to a center housing that is made of iron with high rigidity through joining parts provided at the scroll piece.