The prop sans spinner and the long cowling air intake indicates that this is either a Model 21 G3M2-a with the two retractable turrets or a Model 22 G3M2-b with the big "turtle back" turret without spinners. Possibly Genzan or Mihoro Kokutais (date and location unknown).
Note the combination of two 60kg and one 250kg bombs and the 2-tone top camouflage. Quite puzzling is the way the fuselage Hinomaru looks as if the lower part has faded or is washed-out.
Here's a close-up of the bombs. Emilio in his comment was wright, the 60kg bombs are indeed three. According to FAOW#91, p. 28 this configuration (3X60kg, 1 or 2X250kg) was common during operations in the China theatre. Note their different colours.