A light source device comprising: a semiconductor laser ; a first lens portion having a first lens and a first lens retaining body that retains the first lens and being provided at a position that allows emitted light from the semiconductor laser to pass through the first lens; a second lens portion having a second lens and a second lens retaining body that retains the second lens and being provided at a position that is farther away from the semiconductor laser than is the first lens portion and that allows the emitted light from the semiconductor laser to pass through the second lens; and a housing that retains the semiconductor laser , the first lens portion , and the second lens portion , wherein the housing is a single member that has a first lens retaining recess (1a-1c) and a second lens retaining recess (1d-1f), the first lens retaining recess (1a-1c) including a first surface to which the first lens portion is fixed and retaining the first lens portion , and the second lens retaining recess (1d-1f) including and a second surface to which the second lens portion is fixed and retaining the second lens portion , the first surface is vertical to a direction of an optical axis of the semiconductor laser and wider than a first fixing surface of the first lens portion that is fixed to the first surface, the second surface is parallel to the direction of the optical axis and wider than a second fixing surface of the second lens portion that is fixed to the second surface , and the first lens retaining recess (1a-1c) connects to the second lens retaining recess (1d-1f) in a manner such that a part of the second lens portion is configured to enter the first lens retaining recess (1a-1c). a semiconductor laser ; a first lens portion having a first lens and a first lens retaining body that retains the first lens and being provided at a position that allows emitted light from the semiconductor laser to pass through the first lens; a second lens portion having a second lens and a second lens retaining body that retains the second lens and being provided at a position that is farther away from the semiconductor laser than is the first lens portion and that allows the emitted light from the semiconductor laser to pass through the second lens; and a housing that retains the semiconductor laser , the first lens portion , and the second lens portion , wherein the housing is a single member that has a first lens retaining recess (1a-1c) and a second lens retaining recess (1d-1f), the first lens retaining recess (1a-1c) including a first surface to which the first lens portion is fixed and retaining the first lens portion , and the second lens retaining recess (1d-1f) including and a second surface to which the second lens portion is fixed and retaining the second lens portion , the first surface is vertical to a direction of an optical axis of the semiconductor laser and wider than a first fixing surface of the first lens portion that is fixed to the first surface, the second surface is parallel to the direction of the optical axis and wider than a second fixing surface of the second lens portion that is fixed to the second surface , and the first lens retaining recess (1a-1c) connects to the second lens retaining recess (1d-1f) in a manner such that a part of the second lens portion is configured to enter the first lens retaining recess (1a-1c). <EOS>