Heater module and optical waveguide module

A heater module for heating an optical waveguide device so as to regulate a temperature of said optical waveguide device, which comprises

• a heat-generating circuit adapted to generate heat when energized;
• and
• a heat-transmitting section disposed on an upper face of said heat-generating circuit and the optical waveguide device mounted on the heat-transmitting section, characterized in that:
• said heat-transmitting section is formed with a recessed groove portion for mounting said optical waveguide device;
• wherein a gaseous medium or a resin is interposed in a space defined between walls of said recessed groove portion and said optical waveguide device;
• and
• wherein an upper face of said walls constituting said recessed groove portion is higher than an upper face of said optical waveguide device mounted on a bottom face of said recessed groove portion, or has a level difference not greater than 0.1 mm with respect to said upper face of said optical waveguide device or not greater than {fraction (1/10)} of the height of said optical waveguide device.