$ent = new ElggObject();
$ent->subtype = 'object';
$ent->subtype = 'object_subtype';
$ent->title = 'title';
$ent->description = 'description';
$ent->access_id = ACCESS_PUBLIC;
$ent->owner_guid = 1;
$ent->container_guid = 1;
$ent->site_guid = 1;
$ent->save();

This works.  But I've got a message: "Unable to save new object's base entity information!"

It seems that I have to be logged in, but how can I log in through console? 

Two things:

1. $ent->subtype is set twice. This doesn't matter, but I don't think it's what you meant. Note that you can't go $ent->type = 'type'; The type is controlled by the class. ElggObject is type 'object'.
2. You need to disable access control with elgg_set_ignore_access(true);

Thanks, Brett!