Semiconductor laser device

A semiconductor laser device, comprising:

• a stem;
• a thermoelectric element provided at a position shifted to one side from a center of the stem, on an upper surface of the stem;
• a semiconductor laser configured to be temperature-controlled by the thermoelectric element;
• a heat dissipation block including a first portion, a second portion, and a third portion, the first portion being provided on the one side on a side opposite to the upper surface of the stem and being at least partially provided on a rear surface on the side opposite to the upper surface of the stem, the second portion being provided on the rear surface of the stem and extending from the first portion to just below the thermoelectric element, the third portion being provided on the one side on a side surface of the stem;
• and
• a plurality of lead pins provided around the second portion and penetrating through the stem from the upper surface to the rear surface.